From the Shadows
by TheChasm
Summary: He's survived Tartarus, the Doors of Death and captivity - but Nico di Angelo is far from safe, and his troubles are far from over. Multi-chapter covering Nico's time aboard the Argo II.
1. Chapter I

**Disclaimer: I don't own Percy Jackson. Some of the dialogue in this chapter is taken directly from** ** _The Mark of Athena_** **; I don't own that either.**

 **A/N: So I don't really know where this came from, but... I love Nico? This is going to be a multi-chapter story covering his time aboard the** ** _Argo II_** **during HoH. I hope you enjoy, and please do leave a review!**

 **Chapter I**

Air – he had air again. Aches riddled his exhausted body, and he could not summon the strength to open his eyes, but his lungs had realised that there was fresh air all around him. He took his first deep breath in a week.

All Nico wanted was to lie there on the hard floor beneath him, letting the pain in his hollow chest dissipate, but the back of his neck prickled. He was still in danger.

He struggled onto his hands and knees – even that small movement took a Herculean effort – and began, very slowly, to crawl. He thought he could hear a hissing sound behind him, and a vague image swam to the forefront of his bleary consciousness: his captors, the twin giants Otis and Ephialtes. They had snakes for feet. Snakes hissed, didn't they?

Then the hissing was replaced by predatory growls, and he tried, desperately, blindly, to quicken his pace. The room around him – yes, the bronze jar in which they'd held him had been in a vast underground room – exploded with noise. Yelling and snarling and the clash of metal on metal. Thundering – thunder, underground? There were hands around his shoulders, dragging him to a side, and sharp fear rose in his throat; but these fingers were smaller and warmer than the giants', and anyway he had no strength to resist.

Suddenly there was a gasp close beside him and the grip on his shoulders loosened. The thundering sound got louder – no, not thunder, it was the sound of heavy objects falling around him. That didn't make him feel any safer.

He opened his eyes. He was lying slumped on one side, surrounded by sandbags. This was the giants' room, then – the hypogeum, that was what they'd called it. Not far away, a girl with choppy brown hair was also lying on one side. Her shoulder was bent at an odd angle. The blond boy leaning over her – was that Jason Grace, the missing Roman praetor? – touched her shoulder and she let out a high-pitched yelp, but then said, "Fine. I'm fine."

Nico sat up. The hypogeum was a wreck. Piles of rubble lay scattered at random intervals, and there was no sign of the twins. And there – Nico's heart gave a sudden painful twist. Percy Jackson was standing at the far side of the room, looking warily around. His black hair was tousled and his eyes were as sea-green as ever, and he was as tense and primed for battle as he'd been the first time Nico met him, in the snows outside Westover Hall.

Simultaneously, a mound of dust took shape as the giant Ephialtes, and Otis burst out from under a pile of rubble. Nico fumbled for his sword – where was it? Had they taken it from him once he'd fallen into unconsciousness? Anyway, he doubted he'd be able to stand, let alone raise it.

"Percy!" shouted Jason Grace. "The controls!"

Percy blinked and then drew his bronze sword, Riptide. He slashed it across the control board he was standing behind.

"No!" wailed Ephialtes. "You've ruined the spectacle!"

He swung his spear at Percy and the son of Poseidon fell to his knees, his face suddenly drawn with pain. Jason left the side of the brown-haired girl and ran over to him.

Nico felt suddenly, perilously close to a panic attack. When he'd been captured, he'd been th only demigod alive to know of the existence of both camps, and now Jason Grace and Percy Jackson were fighting side by side. And how had they reached Rome? What were they doing here? His brain felt sluggish and slow, but his heart was thumping far too fast.

"You're both dead," Percy was saying, his voice low and fierce. "I don't care if we have a god in our side or not."

"Well, that's a shame." A god was descending on a platform from the ceiling – Nico didn't recognise him, but there was no mistaking the divine fire flickering in his eyes. "I'd hate to think I made a special trip for nothing."

Two leopards – _leopards?_ Where had they come from? – padded over to him and he scratched their ears. "Really, Ephialtes. Killing demigods is one thing. But using leopards for your spectacle? That's over the line."

The giant choked. "This is impossible. D-D—"

"It's Bacchus, actually, my old friend," said the god. Bacchus... the Roman version of Dionysus. Not the most likely divine champion.

Nico momentarily blacked out. When his vision cleared again, Percy was saying angrily, "What do you consider impressive?"

"Ah, a good question..." said the god. "Perhaps you need inspiration! The stage hasn't been properly set. You call this a spectacle, Ephialtes? Let me show you how it's done."

Nico blinked, and when he opened his eyes again he was no longer in the hypogeum; instead, he was sitting on the stone seats in the old Colosseum, the summer sun beating down on his head. Bacchus was reclining in an elaborate gilded throne to his right, and to Nico's left was the girl with the brown hair, a nymph in a nurse's uniform bandaging her shoulder.

The floor of the hypogeum ascended to show Percy and Jason standing side by side with their swords drawn, facing Otis and Ephialtes. They stared up at Bacchus. The rest of the Colosseum was filled with purple Roman Lares, who fell silent as Bacchus raised a can of Diet Pepsi.

Percy's glare could have stopped rivers – not that he needed help doing that. "You're just going to _sit_ there?" he demanded.

"The demigod is right!" Ephialtes shouted. "Fight us yourself, coward! Um, without the demigods."

"Juno says she's assembled a worthy crew of demigods," Bacchus responded lazily. "Show me. Entertain me, heroes of Olympus. Give me a reason to do more. Being a god has its privileges."

The ghostly crowd cheered.

For a moment, all four combatants stood stock-still, glaring at each other. Nico took the opportunity to turn to the girl on his right and say, "I'm sorry, w-what—"

His voice was weaker than he expected, thin and raspy with disuse. Somehow, she still heard it. She turned to face him, and Nico blinked. He didn't usually notice what girls looked like, but anyone could tell that this girl was seriously pretty: she had long dark hair braided with a white feather, rosy skin and eyes that seemed to shift in colour, blue and green and grey. She smiled at him. "Easy," she said. Her voice was rich and melodious and very soothing. "You're Nico di Angelo? My name is Piper. We're here to save you. We're on your side."

Nico felt his muscles loosen. He leaned back against the stone bench, the panicked feeling in his throat subsiding.

Then Piper gasped and tensed beside him. The twins had just hurled a huge plastic mountain at Percy and Jason.

The two boys dived into a trench. Nico took the opportunity to study Piper more thoroughly. She was biting her lip, looking quite pale with fear, and Nico remembered how Jason Grace had leaned over her in the hypogeum. Her boyfriend? But he was sure he'd never seen her at the Roman camp... In one hand she gripped a strange brown object, almost like a hollowed-out horn. Nico wondered if it was some sort of instrument, but she clutched it like a weapon. A bronze dagger hung at her belt. Not very Roman at all.

Percy and Jason charged out of the trench. The giants had picked up another plastic mountain, but before they could throw it Percy caused a water pipe to burst at their feet, and Otis stumbled backwards, dropping the mountain on his brother. The crowd of ghosts roared.

Otis roared and threw his spear at the boys, but they backed away towards a small lake in the arena floor, shouting insults. Nico caught the words "Swan Lake" and wondered if he was hallucinating.

Jason Grace, who Nico remembered was a son of Jupiter, summoned a blast of wind that shoved Otis into the lake. Percy and Jason brought their blades down together on his head and he crumbled into dust. Nico knew it wouldn't last, though. The demigods needed Bacchus' help to permanently kill the giants.

His heart was beating painfully as he watched Percy charge Ephialtes; his spear clashed with the boys' swords in a brief flurry of action before Jason suddenly stumbled back, blood running down his chest. Beside Nico, the girl Piper screamed.

Ephialtes loomed over the two demigods. Percy was facing Nico, and he looked pale with despair. It was not a look Nico liked to see on his face.

He _must_ be hallucinating. There was no way a Greek trireme could really be descending from the sky above the Colosseum. Still, its shadow felt real enough. What was that as its figurehead – the head of a bronze dragon? The name _Argo II_ was painted on its hull.

Then it fired its ballistae.

Percy and Jason dived for cover, but Ephialtes caught the full blast of the shot. He fell with a thud, groaning. Nico was feeling dizzy. As the warship landed on the arena floor, four figures became visible on deck – and one of them was his sister, Hazel. Her smile stretched from ear to ear.

It was too much, too much. He did not know what he was doing here, and he certainly didn't know why Hazel was here when he'd left her about to embark on a quest from New Rome. Percy had been on that quest, hadn't he?

Nico's fingers were starting to feel cold. Now Bacchus was parading jubilantly around the stadium, saying, "Of course I did something. I killed two giants!"

The ghosts cheered.

"Come on," said Piper. With a jolt, Nico realised she was talking to him. In a daze, he followed her down the stone steps onto the arena floor.

Jason ran to meet them. Although the guy had just been through a battle, his bright blue eyes sparked with energy. "Pipes – you okay?"

"I'm fine," Piper said impatiently. "But your wound—"

"I'll be okay," said Jason. "It's not deep." He glanced at Nico and smiled awkwardly. Nico was used to that.

Nico didn't have the energy to speak, to do anything more than fight to stay upright. Black spots were dancing in his vision, but he stared at the other cluster of demigods. Bacchus had disappeared, as had his ghostly audience. Percy was talking to a short Latino boy with a shock of black hair and a completely manic grin. Hazel and Frank Zhang were standing beside him.

"Where's Annabeth?" Percy demanded, his voice carrying over the distance between them.

Nico's heart felt suddenly cold. Annabeth Chase. Even after his seven months' disappearance, Percy still cared. Of course he did.

The floor was shaking now. "Let's get on board," Piper said urgently. She and Jason ran for the rope ladder extending down the side of the ship, and Nico hobbled after them.

As he reached the ladder, a warm hand touched his wrist. Nico hated physical contact, but he didn't mind when he turned to see Hazel's warm golden eyes smiling into his. "Nico," she said. Just his name, like a prayer.

He couldn't speak; his throat was suddenly tight. He twined his fingers through hers.

"Come on," Hazel said. "Let's get you to safety."

He had to be practically hauled up the ladder. Leaning on Hazel, he hobbled over to the stern of the ship, where she sat him down on a low bench and pulled some ambrosia from her backpack.

Nico had brought food with him from Los Angeles when he'd gone into the Underworld, but after he'd been drawn into that place, the place he had to keep in a locked-up corner of his mind or he would go insane, he hadn't eaten. He didn't think he'd wandered long down there before his capture, and since then, he'd only had the magic pomegranate seeds in the giants' bronze jar.

Logically, he knew he was more than half-starved. But staring at the chunks of ambrosia he realised that he didn't feel hungry.

"Here," Hazel murmured. She pressed a piece to his mouth and he swallowed obediently. It tasted, like it always did, of spaghetti bolognese, both his and Bianca's favourite dish. Bittersweet, like it always was. But he could not think of Bianca now or he would fall into a million pieces and they would never be able to sweep up the fragments.

"Hazel... what is this ship?" he asked. He didn't realise how quiet his voice was until Hazel leaned in to catch his words. Her lovely eyes were dark with worry, worry for him. The thought warmed him a little, though his fingers still felt numb and his head was heavy.

"Do you know the Prophecy of Seven?" she asked. Nico nodded. He'd been there when Rachel Dare had first recited it, and later he'd learned that the Romans had known it for hundreds of years. Hazel wetted her lips. "We – me, Percy, Frank, Jason, Piper, Leo and Annabeth Chase are the seven of the prophecy. Leo – he's a Greek demigod, not Roman like us, and so are Percy and Piper and Annabeth – he built this ship so we could fly to the ancient lands and hopefully defeat the giants."

"Hazel," Nico said gently, "you know that I'm a Greek demigod too, don't you? I'm the son of Hades, not Pluto. I've known Percy and Annabeth for years." He thought he managed to say all this without his voice giving him away.

Hazel's eyes darkened again. "I know," she murmured, and Nico wondered if she was angry with him. The thought was almost more than he could bear.

"I'm sorry," he whispered.

To his relief, his sister smiled at him. "It's alright. You did what you had to do. But where have you been, Nico? You said you'd search for the Doors of Death from the other side, and then Gaia told me in a vision that you'd been captured... did you find them? Where are they?"

Nico stared over her head. The ship was flying high above the city of Rome. Everything seemed so peaceful, the bright blue sky and the Italian sun.

"Nico?"

He met her eyes again. "The darkest part of the Underworld," he said, voice very low. "Where even Hades doesn't venture. They're... they're in Tartarus."

Hazel gasped. "You've been there? To Tartarus? Gods, Nico..."

He didn't want to talk about it. He didn't want to remember, and they were pressing against the edges of his consciousness now, the memories of what he'd seen there. He couldn't let them in.

He forced himself to continue. "The Doors have two sides," he told his sister. "One... one there, and one in the mortal world, in Greece. Gaia has huge forces guarding both sides... they overwhelmed me as soon as I got near. Then they brought me through into the mortal world and took me to Rome, and the giants stuck me in that jar." His hands were trembling now. Hazel pressed them between hers, warm and steady.

"He reads Chinese," the boy called Leo was telling the other demigods. Did he ever stop grinning?

Frank Zhang hunched his shoulders. "Just a little bit."

"How cool is that?" Leo exclaimed.

"Guys," Hazel called. "I hate to interrupt your admiration session, but you should hear this."

She put a hand beneath Nico's elbow, helping him to his feet. He had to lean on her to shuffle the few steps over to the other demigods... and to Percy.

Nico didn't like being stared at, and he didn't like being the centre of attention. His rescuers were looking him with pity and curiosity mingled in their gazes. He took a breath. Never, he thought, would he take a wide expanse of air for granted again.

"Thank you," he said, looking around the group. "I'd given up hope."

Percy was looking intently at him. Nico tried to meet his gaze levelly. He tried not to blush.

"You knew about the two camps all along," Percy said. To his credit, there was no hint of accusation in his voice, just a sort of detached curiosity. "You could have told me who I was the first day I arrived at Camp Jupiter, but you didn't."

Hazel wasn't holding Nico's elbow any more. He swayed and then slumped against the ship's helm. "Percy, I'm sorry. I discovered Camp Jupiter last year. My dad led me there, though I wasn't sure why. He said the gods had kept the camps separate for centuries and that I couldn't tell anyone. The time wasn't right. But he said it would be important for me to know..." He'd been talking too much; his lungs couldn't stand the strain. A spasm of coughing broke out, and he doubled over, but Hazel was there, holding him until it passed. "I – I thought Dad meant because of Hazel," he carried on. "I'd need a safe space to take her. But now... I think he wanted me to know about both camps so I'd understand how important your quest was, and so I'd search for the Doors of Death."

Sparks flew from Jason Grace's hands. Nico wondered if that often happened when he was nervous, and if it was safe for him to stand near plug sockets.

"Did you find the doors?" asked Percy.

Nico nodded. "I was a fool," he said bitterly. "I thought I could go anywhere in the Underworld, bit I walked right into Gaia's trap. I might as well have tried running from a black hole."

Frank chewed his lip. "Um... what kind of black hole are we talking about?"

Nico wanted to answer him, but the words stuck in his throat. The memories were hissing at him louder now, begging his fragile consciousness to give in to their onslaught. He fought back a shudder and turned to his sister.

Hazel put a hand on his arm and began to explain to the others about the mortal side of the doors.

Piper's horn spat out a cheeseburger. Not a musical instrument, then. "Where exactly in Greece is this doorway?" she asked.

Nico took a breath. "The House of Hades. It's an underground temple in Epirus. I can mark it on a map, but – but the mortal side of the portal isn't the problem. In the Underworld, the Doors of Death are in... in..." He couldn't say it, he couldn't.

Percy's eyes turned dark. "Tartarus," he murmured. "The deepest part of the Underworld."

Nico nodded. "They pulled me into the pit, Percy. The things I saw down there..." His voice faltered, and for a moment his vision went completely dark, and the memories pressed closer and closer but he could not break down now, not here.

Hazel had been talking, but now she stopped. Everyone was staring at him. Hazel passed him his sword – where had she found it? – and he wrapped his fingers around its familiar hilt, but he didn't have the strength to do much more than lean on it.

"Now I understand why Hades hasn't been able to close the doors," he said. "Even the gods don't go into Tartarus. Even the god of death, Thanatos himself, wouldn't go near that place."

"So let me guess," said Leo. "We'll have to go there."

Nico shook his head, inwardly marvelling. "It's impossible. I'm the son of Hades, and even I barely survived. Gaia's forces overwhelmed me instantly. They're so powerful down there... no demigod would stand a chance. I almost went insane." Maybe he was.

Percy was looking at him with pity and sadness and shock, perhaps more tenderly than he'd ever looked at Nico before. "Then we'll sail for Epirus," he suggested. "We'll just close the gates on this side."

"I wish it were that easy," Nico said. "The doors would have to be controlled on both sides to be closed. It's like a double seal. Maybe, just maybe, all seven of you working together could defeat Gaia's forces on the mortal side, at the House of Hades. But unless you had a team fighting simultaneously on the Tartarus side, a team powerful enough to defeat a legion of monsters in their home territory—"

"There has to be a way," Jason said, sounding more wishful than confident.

The ship was descending towards a palatial building. Percy glanced down and his eyes darkened. "We'll figure out the Tartarus problem later. Is that the Emmanuel Building?"

Leo nodded. "Bacchus said something about the parking lot in the back? Well, there it is. What now?"

"We have to get her out," Percy said. Nico had only seen an expression like that, all barely-controlled fear and fierce protectiveness, once before: on Annabeth's face the last time he'd seen her in December, when she'd begged him to help her look for Percy.

"Well, yeah," said Leo. "But, uh... there's a parking lot in the way."

"Bacchus said something about _breaking through,_ " said Percy. "Coach, you still got ammo for those ballistae?"

Nico hadn't really noticed the satyr before: unlike Grover Underwood, he was middle-aged, with much larger horns and goat legs that he made no attempt to hide. He was grinning crazily. "I thought you'd never ask."

As the satyr ran for the ballistae, Nico frowned. "Annabeth... she's down there? What's she doing?"

"She's been on a solo quest," Hazel explained. "Following the Mark of Athena."

Nico blinked. The words sounded familiar... he thought he'd spoken to the ghost of a demigod child of Athena about this, long ago, but the details eluded him. "What is that?"

"It's like a trail under the city of Rome," said Piper. "It leads to the Athena Parthenos."

"The lost statue in the Parthenon?" Nico's head was spinning. "It's in Rome? But why do you need it?"

Hazel took his hand. "Because the Greek and Roman camps are at war," she said quietly. "The legion is marching on Camp Half-Blood right now. And we think the statue is the only thing that can heal the rift."

"War," Nico repeated hazily. "But... you're all working together – how – and surely Reyna would never be so rash—"

Jason made a growling sound in his throat. "It's not Reyna who's pushing for war," he said. "It's Octavian. If I ever get back to Camp Jupiter, I swear—"

He was interrupted by a whoop from the satyr as the ship's ballistae fired. Beside him, Percy grinned. Leo manoeuvred the _Argo II_ into the gaping new hole in the car park as cars tumbled through.

Percy ran to the side of the ship as they descended into a huge underground cavern. "Annabeth!" he called.

"Here!" The response was little more than a sob.

Nico and the others stared around in astonishment as the ship hovered to a stop about forty feet from the floor. Only Percy moved, sliding down the rope ladder with almost inhuman speed and running over to where Annabeth Chase was standing, staring into a dark hole in the floor. More astonishing, though, was the gigantic statue of Athena filling the cavern with warmth and light. Nico had seen the goddess before, and her ivory face was a perfect likeness. Her robes gleamed purest gold, and she held out a life-sized statue of the goddess Nike in one hand.

"She's beautiful," Piper breathed.

"Come on," Jason murmured, and they followed Percy down the rope ladder.

Percy had reached Annabeth. She hid her face in his chest and burst into tears. "It's okay," Percy was saying, voice low and soothing. "We're together."

Nico took a deep breath, trying to ignore the sharp pain in his chest.

"Your leg," said Piper, reaching out to touch a bubble-wrapped cast around Annabeth's ankle. "Oh, Annabeth, what _happened?_ "

It was, for sure, an impressive story. Nico knew he would never have had the courage to inch across a gaping chasm on a woven bridge, nor would he have survived Annabeth's encounter with the ghostly followers of Mithras. And the monster waiting for her at the statue had been Arachne herself. Nico wasn't even afraid of spiders, and he couldn't imagine how poor Annabeth had faced the monster.

As she talked, he looked around the cavern. It was littered with spider silk; some was trailing from Annabeth's legs and arms, too, and holding together the cracked floor. This cavern was unstable. He wondered whether removing the statue would even be safe.

"Well, it might take some rearranging," Leo was saying, "but I think we can fit her through the bay doors in the stable. If she sticks out of the end, I might have to wrap a flag around her feet or something."

Annabeth shuddered. "What about you guys? What happened with the giants?"

Oh... Nico did _not_ want to listen to this part of the story. He kept his gaze fixed on the statue as Percy explained about the fight with the giants and their conversation aboard the _Argo II._ Annabeth was giving him that same pitying, half-scared look, as though he was a wounded wild creature who would bite if not handled gently.

"So the mortal side is in Epirus," she said. "At least that's somewhere we can reach."

"But the other side is the problem," said Nico. "Tartarus." Now he wanted to keep saying the name, over and over again, to prove to himself that he wasn't afraid. (But he was afraid.)

The hole behind them exhaled a cold blast of air as he spoke. Nico fell suddenly silent. This hole... it led there. It led to the pit. And the only thing keeping him from falling in was a floor full of cracks, held together with spider webs. He was feeling dizzy again, but this time with fear.

As if following his thoughts, the chamber groaned and the Athena Parthenos tilted ominously. Annabeth paled. "Secure it!"

"Zhang!" Leo cried. "Get me to the helm, quick! The coach is up there alone."

Frank nodded and stretched out his arms. His fingers sharpened into claws. Feathers sprouted along the length of his arms and back, and his nose narrowed to a wicked beak. He was... a giant eagle. Since when had he been able to do that?

Although Nico was gaping, none of the others seemed to see anything out of the ordinary. Jason wrapped his arm around Piper's waist, said, "Back for you guys in a sec," and then shot into the air. Percy gripped Annabeth's hand tightly and led her further away from the edge of the pit.

"This floor won't last!" said Hazel. "The rest of us should get to the ladder." She lunged for the rope ladder and then turned back to gesture at Nico, who stumbled after her. His chest felt tight and his vision was washed in red. What if... what if he didn't make it?

He'd gone nearly blind by the time he reached the ladder, but at last his hand closed on rough rope and he let out a shuddering breath. Tiny tremors were racking his whole body.

"Her ankle!" Hazel shouted from just above him. "Cut it! Cut it!"

Nico looked over his shoulder. Annabeth had fallen flat on her face, being dragged backwards by a rope of silk wrapped around her bad leg. The spider was still there.

He hobbled back towards Percy, who was clutching Annabeth's hands, but he was still moving painfully slowly and Hazel, behind him, had got her _spatha_ entangled with the rope ladder. Nico was the only one close enough to help, but he couldn't move fast enough.

"Help them!" Hazel screamed, but over the din of the others trying to secure the statue, nobody heard her.

He reached the edge of the pit just as Percy and Annabeth tumbled over. Shaking, Nico peered over the edge. Percy had caught onto a tiny ledge about fifteen feet below the edge. Annabeth dangled helplessly beneath him, only his hand keeping her from falling into the void.

There was a high-pitched whining noise in his head, and he had to fight to stop frightened tears spilling out. He couldn't go back. He was so close to the pit, but he couldn't go back. He would die before he entered that place again. Shuddering, he stretched out his hand, but Percy was much to far away to reach him.

Percy stared up at Nico, eyes wide and bright with fear, and then down at Annabeth again. "Percy, let me go," she gasped. "You can't pull me up."

He could do it. If he let go of Annabeth, Percy was strong enough to pull himself onto the ledge, and then Nico could reach across the distance to him. He could do it. But of course he wouldn't.

"Never," he said, his voice trembling with effort. He tilted his head back to look up again. Nico had known Percy Jackson for some three years now, and in all that time he'd never seen despair and determination mingle so fiercely in his sea-green eyes. "The other side, Nico!" he called. "We'll see you there. Understand?"

Nico did, but he didn't want to. He thought his heart might tear itself in two. "But—"

"Lead them there!" Percy shouted. His eyes sparkled with intensity. "Promise me!"

Nico didn't want to say it. He didn't want the words to come out of his mouth. But it was Percy and Nico could not refuse him, could not argue when those eyes were boring into him as though he were the only person in the world, and so he said, "I – I will."

Percy looked at Annabeth. "We're staying together," he said. "You're not getting away from me. Never again."

Tears were running freely down Annabeth's face, but her voice was steady. "As long as we're together," she said.

Nico watched, his hand still extended uselessly below him, as Percy let go of his tiny ledge, and he and Annabeth were swallowed by the darkness.

He could not move. He could not breathe. Perhaps part of it was shock paralysing his bones, but it was more than that. The force of the Underworld tugged at him, hungry. Demanding. The pit had not been happy that he'd escaped it. The pit wanted him back. And he knew, with a sudden cold certainty, that he was going back there, fighting was useless and resistance was pointless because the pit wanted him back to finish its game and the pit _always_ got its wish. But he could not go back. He had a promise to keep.

 _Come back,_ the pit seemed to purr in his mind.

"Nico!" Hazel screamed. And then she was beside him, her hand warm and tight around his wrist, and she was forcing him to run as chunks of ceiling fell ahead and behind them and the floor of the ancient cavern crumbled into the pit.

He couldn't really run, but Hazel was pulling him onward, so fast that his lungs burned in protest, and then they slammed into the side of the ship and clung to the edge of the rope ladder for their lives.

"Percy," Hazel moaned. "Percy and Annabeth..."

"They're gone," Nico choked. His sister gave a sob.

The floor was giving way completely. Only a few seconds more, and they would both fall, rope ladder or no – and then there was a pair of firm hands on his shoulders, and Nico went completely limp as the sky seemed to fall towards him and the ladder slipped from his numb fingers, and then Jason Grace set him down on the ship's deck. Beside him, a giant eagle landed on the deck with Hazel in its claws and turned back into Frank.

"Go, Leo!" Hazel cried, and at the helm of the ship the dragon figurehead roared. The ship soared out of the cavern seconds before the roof caved in.

"Where are they?" Piper demanded, gripping her bronze dagger.

Nico's legs gave way and folded beneath him. He sank down onto the floor. "They fell," he said. "Into... into the pit."

Jason, Frank, Piper and Hazel all stared at him. Nico didn't want to meet their gazes. He stared at his knees, hollow and desolate. _He was gone._

The ship settled on a hill just outside Rome. Leo ran over, scanning the group, paling as he came up two short. "Percy and Annabeth?"

"We were too late," Jason said dully. Leo shook his head.

"We have to go back there," Hazel said. "Maybe we'll find them."

"Hazel..." Nico trailed off. He'd seen them fall. He knew they were gone. But he was the only one.

Frank turned into an eagle again, and Hazel clambered onto his back. "I'll come, too," Jason offered, and he flew off behind them.

Nico looked up. Piper and Leo were the only other demigods on the ship – the two he knew least well. He realised he didn't even know who their godly parents were. Leo kept casting him nervous looks as they talked quietly with each other. He was afraid of Nico. Well, nothing new there.

Nico thought of how the campers at Camp Half-Blood had cast him those uneasy sideways looks if he ever appeared beside them or came to sit at their table at dinnertime, even after the Battle of Manhattan. Had they thought he didn't notice them? Perhaps they thought children of the Underworld didn't have feelings, anyway.

Percy hadn't been like that. He'd always greeted Nico with a smile – but it had been too painful, being with Percy once he and Annabeth started dating.

And now Percy was gone.

Hazel, Frank and Jason were back sooner than Nico expected. The boys' faces were grim. Hazel looked like she had been crying. She slid out of Frank's grasp and sat down beside Nico, which made him feel a little better.

"The cavern's been buried," Jason said wearily. "We tried to dig through the rubble, but... but it's just gone."

"None of the mortals were hurt," Frank added. "And the entrance to the pit is sealed off. But..."

Piper stared at the huge statue hanging behind the ship, still tangled in the grappling ropes. "Annabeth saved the statue," she said, voice trembling. "We have to take care of it. Come on."

The others stumbled after her like sleepwalkers, but they managed to load the statue into the ship's bay. Nico wasn't sure, but he thought he saw Frank turn into an elephant at one point. Since when did klutzy Zhang have all these cool powers?

Hazel had stayed sitting beside him. For a few moments they were quiet. Then Hazel spoke. "Are they dead?" Her voice was very low.

Nico had already asked himself that. "No," he said. "I don't think they are. Do you?"

She glanced at him uncertainly. Hazel had never had many powers over the dead. Her sphere was riches, not death. But she closed her eyes for a moment, before saying, "I don't think so."

"You'd know if they were," Nico told her. "When it's someone you know... well, you'd know if they died." He thought of the day three years ago when he'd felt a sharp, stabbing pain in his chest. Nothing serious, or prolonged, and he hadn't thought much of it at the time. But a few days later Percy Jackson had come back to camp and told him his sister was dead.

Hazel folded her fingers around his, and he let himself lean into his sister's shoulder. She wasn't Bianca, but that didn't mean he couldn't love her.

"I was so afraid," she murmured now. "The whole time... It's – it's awful that Percy and Annabeth are gone, but I'm glad you're okay."

"I'm not," Nico said, before he could stop himself. Then he took a breath. "I'll be fine, though. I promised Percy—" the name was difficult, but he kept his voice steady – "I'd lead you to Epirus. You'll need my help to get to the Doors of Death. We can meet them there."

"You think they can survive there?" Hazel looked at him as though he was made of silk and feathers and the slightest breath would blow him away.

"If anyone can, they can," Nico said, hoping he sounded more confident than he felt.

The rest of the crew, and the satyr called Coach, were making their way back towards them. Hazel stood and extended a hand to Nico. He took it, and she wrapped her arms suddenly around him.

Nico didn't try to pull away, for once. He hid his face in his sister's shoulder and finally – _finally_ – let the tears come.


	2. Chapter II

**Disclaimer: I don't own Percy Jackson.**

 **A/N: I hope everyone enjoys this new chapter – do let me know what you thought!**

 **Chapter II**

The first attack was from a group of telkhines, and then they were followed by Cyclopes and hellhounds, and an _empousa_ raked her claws across his face, and soon he was overwhelmed and his overtired mind began to collapse as the images blurred into each other and all he could feel was the endless pain, and the voice of the pit always in his mind: _You are nothing, little demigod. Give up. Give in._

Nico screamed and sat bolt upright in the bed, reaching for his sword. It wasn't there and he panicked for a moment before his senses returned to him: he'd been rescued. He was safe. Still, it took a little longer for him to realise that he was still screaming, and to stop.

He looked around him, trying to slow his heartbeat. Yes, he remembered where he was. Hazel had brought him to the _Argo II_ 's sickbay for rest. He was lying in one of the beds there... gods, when was the last time he'd slept in a proper bed? Camp Jupiter, probably.

The door banged open and a girl rushed in. For a moment, Nico thought it must be Hazel, but then he saw the braided dark hair and pale face. Not Hazel, but the other girl. Piper. Just his luck.

She had drawn her dagger, though she was still in her pyjamas, and her shoulders took a moment to relax. "Oh... Nico, are you okay?"

"Yeah," Nico managed. "Fine. Sorry to wake you..."

And they could have left it there, but then something seemed to snap in the recesses of his mind and for the second time that day he found himself in tears. Piper didn't say anything, or try to touch him, which he appreciated. She just sat down on the edge of his bed and handed him a tissue. Soon he recovered himself enough to take it and wipe at his eyes fiercely.

"S-sorry," he said. Gods of Olympus, what was wrong with him? Breaking down in front of a random girl he'd known for less than a day...

"If you want to talk, I'm right here," Piper offered tentatively. She didn't sound keen. Who wanted a heart-to-heart with the son of Hades?

He shook his head, trying to steady his breathing. "I'm okay, thanks."

Piper tilted her head and gave him an appraising look. "I can't imagine what it must have been like," she said softly. "There's no shame in having nightmares, you know."

A sound came out of his throats that was half sob and half bitter laugh. "Yeah?"

"I have them," Piper said. "And I haven't been through anything compared to you."

She was trying to be kind to him, so Nico tried not to mind the nervous, wide-eyed looks she kept giving him. He remembered how she'd been injured in the hypogeum, trying to save him. "Thank you," he said quietly.

Piper smiled. "Hey, we all have moments. It's nothing to be ashamed of. And... everything happened so quickly today, but I guess you have a lot of questions."

Nico blinked. The girl seemed almost to be pulling thoughts half-formed from his mind, melding them into sentences faster than he could recognise them. "You're very perceptive," he murmured. "You read people well. And you're good at getting people to do what you want. Your godly parent... Aphrodite?"

She grinned. "You're good. Keep going."

"But I don't get it," Nico said. "Your voice... it was like you were working magic on me, back in the Colosseum. That's not normally a power of Aphrodite, is it?"

Piper's expression was suddenly pensive. She turned her dagger over in her hands, staring at the bronze blade as if expecting it to show her something. "I'm a charmspeaker," she said at last. "It's quite rare. But I can convince people to do what I want them to, sometimes."

"Oh." Nico wondered if this pretty, harmless-looking girl was actually one of the most dangerous demigods on board the ship. "That's... useful, I guess."

She raised her good shoulder in a half-shrug. "Yeah, mostly. Not the most use in a fight, though, a dagger and a pretty voice."

"Why do you carry it?" Nico asked curiously. "Most demigods use swords."

Piper wrinkled her nose. "I suck at sword-fighting. And this isn't any old dagger, anyway. Its name is Katoptris."

"Looking-glass," Nick translated automatically. "It... shows you things?"

Piper nodded. "Visions. Glimpses of the future, or the past. We used it to find you, actually."

Nico wasn't sure quite how to respond, and his conversational powers were running low. "Thank you."

Piper smiled. "Tired? I'll let you sleep. Come and chat to me if you ever need to, okay? Hazel's an amazing girl, but I guess there are some things you don't really want to talk to a sister about."

Nico blinked. Why was she being so kind to him? "Thank you," he said again, tremulously, and Piper smiled at him again as she walked out of the sickbay.

Nico lay back down and stared at the ceiling, but his eyes refused to close. His pulse was still racing from his nightmare. Strange, how all through those eight endless days in the bronze jar his sleep had been dreamless, and it was only now that he was safe that the memories came flooding back. Or maybe he wasn't really safe at all. Maybe _safe_ was an illusion.

He shuddered. Perhaps he should walk around for a while. He slipped out of the bed and shivered in the cool night air. Leo, who was closest in size to him, had given him a spare pair of pyjamas, and there were soft slippers lying under the bed, but in them he felt oddly vulnerable. He put on his tattered black aviator jacket like it was armour.

The ship was silent. Nico prowled down the cabins filled with sleeping crew, poked his head into the engine room, and passed what appeared to be stables – though he didn't see what they were doing on a ship, and anyway the Athena Parthenos filled most of the space on the lower deck. Its ivory toes poked into the sickbay where he'd slept.

He slipped up to the deck for a while, where Jason and Leo were keeping watch by the prow. They were talking in low voices and didn't notice him, so he gave himself the luxury of a little while in the open. Usually, he wasn't an outside person – he much preferred being underground – but after the bronze jar, he felt more than a little claustrophobic. The cool wind soothed him.

Safe, he told himself. For now at least, he was safe.

oooooooooo

In the morning he found Hazel and Frank sitting side by side in the mess hall. The hall was a large, beautiful room, with one long table covered with dirty dishes and scrap pieces of paper that had been used, as far as Nico could see, as maps, lists of random ideas, paper aeroplanes and (for some reason) a brownie recipe. The room's walls were broadcasting real-time images of Camp Half-Blood, where it was now the middle of the night: Thalia's pine tree, the ring of cabins, the beach. Nico stared at them. Camp Half-Blood wasn't his home. But it was the last place he'd seen Bianca, the only place he'd ever felt welcomed or accepted, if only for a few short days.

"Hey," said Hazel, jolting him out of his thoughts. "Sleep well?" She smiled at him, but her eyes were still concerned. Nico nodded. Well, he'd slept, at any rate. For, like, an hour.

"What's the plan?" he asked, sliding into the seat beside her. Then he stiffened. Frank Zhang's large hand was sitting quite naturally on top of his sister's small, delicate one, as if it belonged there, and Hazel herself looked perfectly at ease with the whole situation. She wasn't even blushing.

"Jason and Leo are still asleep – they took the night watch," Hazel explained. Nico tried to tear his gaze away from the offending sight. "When they wake up, we'll have a crew meeting, decide on our course. Til then, me and Frank thought we'd show you around the ship for a bit?"

"Uh, actually..." Zhang looked supremely uncomfortable – as he should, keeping his hand on Hazel's as if Nico wasn't _right there._ "I – I got to see if I can whittle out some more arrows, I lost a fair few yesterday..."

He trailed off, noticing Hazel's disappointed look, but then she smiled up at him as he stood. "Sure. See you later."

As soon as he was out of earshot, Nico turned to his sister. "You and Frank?" He couldn't keep the incredulity out of his voice.

 _Now_ she was blushing. "Yeah... after we came back from Alaska. He's really sweet, Nico."

Looking at her, Nico's protective irritation faded. Hazel seemed so much more sure of herself now than she had when he'd left her in New Rome, at ease and confident with her new friends. If that was partly because of Frank, he supposed he should be pleased. "Does he know about your past?" he asked.

Hazel nodded. "Everyone does. It... it doesn't seem like such a big deal now, for some reason. And Frank and Percy were so kind..."

Nico's nerves were on edge. At Percy's name, he flinched, but Hazel didn't notice. The atmosphere in the mess hall seemed to have darkened.

It took him a moment to realise that she had turned back towards him, frowning at the empty plate in front of him. "Aren't you going to eat something?" she asked. "You still look so ill."

"I'm not really hungry," Nico said, but at her look he sighed. "Fine." The plate looked to be magical. "Toast and jam." Immediately, a thick slice of white bread appeared, toasted to perfection and slathered with strawberry jam.

Hazel smiled. "Eat up," she said. "And I'll tell you everything that's happened."

 **oooooooooo**

It took Nico a long time to finish his breakfast. The bread tasted dry as sawdust and the jam was sickly sweet after the sourness of the pomegranate seeds; it seemed to stick in his threat as he tried to choke it down.

As he struggled, Hazel talked to him, filling him in on everything he'd missed during his captivity. She told him about their quest to free Thanatos, how she and Frank had killed the giant Alyconeus while Percy kept his army at bay, how Polybotes' army had invaded Camp Jupiter and Percy had defeated him and been raised to praetor on the battlefield. She described how the four Greek demigods and the chaperone, the satyr Coach Hedge, had arrived soon after in their flying warship, how they'd been building a tentative sort of friendship before Gaia had interfered as usual, and Leo had accidentally fired on the camp.

By then, Nico had finished eating. Hazel took him by the hand and let him around the ship, talking all the while. "Gaia sent me a vision in Alaska," she said. "She told me you'd been captured... I knew we had to save you. But it was more than that." She told him about the prophecy that the freakishly smart harpy Ella had recited, how Nico _held the key to endless death_ , and how she'd convinced the others that rescuing him was vital to the quest.

Nico listened to this part detachedly, as if she were talking about someone else. Of course he was happy that Hazel had been so loyal, but he couldn't seem to summon up any feeling, any expression beyond a wan smile.

He'd eaten the seeds because they were there, and because, by Hades, he wasn't going to die without a fight, but almost right from the beginning of his time in the bronze jar he'd told himself that it was hopeless. No one would be coming for him. Now, with his sister's hand warm and firm on his and her voice telling him that he was important to her, his heart felt sort of hollow, but sort of full as well.

Hazel told him about the _Argo II_ 's journey across America, how they'd met Nemesis and Bacchus and the sea god Phorcys, and how the Romans had chased them all the way to Charleston before turning back to attack Camp Half-Blood instead. She explained how the Athena Parthenos was a symbol that could heal the rift between the gods' two sides, and how vital Annabeth's quest to save it had been. She talked about their journey across the Atlantic, how she'd met the ichthyocentaurs under the ocean and how they'd survived encounters with Hercules and the pirate Chrysaor, until Nico's head swum with details.

Dread settled in his stomach as he wondered what he'd managed to get himself into. This quest was the greatest demigod undertaking for many generations, a race against time to seal the Doors of Death, defeat the giants and their armies and prevent the rise of Gaia. The demigods on this ship all had some special talent, whether it was Piper's charmspeak or Leo's fire use or Frank's awesome shape-shifting. They were the prophesied seven; they were heroes. What was Nico doing here?

He'd been too dazed the day before to think much about his next steps, but they certainly hadn't included joining the crew of the _Argo II_ , a ship filled with other demigods who would look at him with their frightened mistrustful eyes and stop talking when he came too close. If he had his choice, he would find a way back to the Underworld and his father's palace, take refuge in the halls of the dead.

But he didn't have his choice. Percy Jackson had seen to that.

Hazel squeezed his hand. "Okay? You're so quiet."

Nico managed a smile. "Yeah," he said. "It's just... a lot to take in."

"Everyone here is really nice," Hazel promised. "You'll adjust quickly. Come on, it's time for the crew meeting."

Nico wanted to protest that he wasn't part of the crew, but Hazel dragged him up above deck. The other demigods had all gathered there: Coach Hedge was steering at the helm, while Piper stood on watch amidships, holding her dagger at the ready. Her expression was guarded, but she smiled at Hazel and Nico as they came over. Jason and Leo stood nearby, rubbing sleep out of their eyes. Frank was also there. For some reason, he was giving Leo a hostile look.

Jason clapped his hands. "So. What's the plan?"

Leo was holding a hastily sketched map of Italy. "So, here's Rome," he said, pointing to where the city was marked. The others gathered around him to look over his shoulder. "We've been flying north since yesterday – I, uh, figured we wanted to put some space between us and that place. So we could keep heading north, or..."

Jason glanced at Nico. "Nico, you said you could lead us to the House of Hades. Where is it?"

Nico took a breath. The other demigods were all looking at him expectantly. "Epirus is on the western side of Greece," he said. His voice still sounded paper-thin and weak, even to his own ears. "The temple is near the River Acheron."

Leo unfolded his map to show the eastern part of the Mediterranean and a rough outline of the Greek coastline. "Could you point it out on here?"

"Here." Nico tapped a point on the Greek mainland, not far inland.

"Okay," said Leo. "So this looks pretty straightforward."

"Don't say that," Piper warned. "You'll jinx us."

"Look, though," said Leo. "We've got to go straight east across Italy. Then we can sail down the Adriatic all the way to Greece. At top speed it'll take two to three days, tops."

Hazel frowned. "But how can we be sure Percy and Annabeth will meet us at the same time?"

"Nico, you've been there," said Leo. Nico noticed he wasn't meeting his eyes. "How long do you think it will take them?"

Nico stiffened. He wasn't ready to talk about his time in the pit, and especially not to a group of near-strangers. Beside him, Hazel gave Leo an angry glare. "I – I'm not sure," he admitted. "Time works differently down there. And I... I don't really remember..." He did his best not to shiver.

"That's okay," said Piper. "Don't worry about it. But Hazel is right, guys. If we reach the Doors without Percy and Annabeth controlling the other side, we can't close them, or get them through."

Nico had been barely conscious by the time they'd brought him through the Doors, but he thought he remembered the Titan Hyperion standing guard outside it, keeping his finger on the elevator button for the twelve long minutes it took to get up to the mortal world. Even if Percy and Annabeth reached the Doors of Death, one of them would have to stay behind in Tartarus to let the other through. Nico knew Percy well enough to know what he would do then.

He decided not to share this.

"We'll have to worry about that problem when we get there," Jason decided, as if he were reading Nico's mind. "Leo, set the course east. Pipes – you okay to keep watch some more, or...?"

"Frank and I can take our turn," Hazel volunteered. "We haven't gone yet."

"I'll help," Nico said quietly, and then wondered what he was doing.

Hazel gave him a concerned once-over. "If you're sure you're up for it."

"I can do it," Nico insisted. He looked around the ship and his eyes alighted on the crow's nest at the top of the mainmast. He pointed. "I can keep watch from up there."

The rest of the crew was dispersing, but Hazel still looked worried. She stood nervously on the deck as Nico began to climb, looking as though she wanted to call out encouragement but was afraid to distract him.

Nico was an agile climber, though, and once he reached the top he gave her a reassuring wave. Then he took stock of his surroundings. The crow's nest was small but sturdy, with a splendid view of the Italian countryside in the morning sun. Up here there was no sound but the rushing of the wind and his own breathing. Away from the others, the uneasy prickling in his throat died down.

Yes, this was a good place. He was safe here, almost on the top of the world.

He settled down to watch.

 **oooooooooo**

They drew near to the Apennines in the middle of the afternoon. The mountains loomed up at them with frightening suddenness, and Nico's neck prickled as he looked at them. The peaks were cloaked in fog, and the dark rock did not look friendly.

"Get us higher!" he called down to Leo, who was at the helm again. "I don't like the look of these."

Leo shook his head. "There's only so high the ship can go! We'll have to go between the peaks."

Nico bit his lip, but he didn't argue. They plunged into fog.

The temperature dropped so suddenly that he gasped; his breath misted in front of him. He could barely see Leo, forty feet below him.

Nico tried to fight back the panic rising in his throat. He was still here, outside in the upper world, with the wind on his face and the sun just above him – but it all felt so sickeningly familiar...

 _Did you think you had escaped me, son of Hades?_ the voice of Tartarus seemed to be purring in his head.

Nico gripped the edges of the crow's nest. No. He was still here. He was still here. But the fog was thickening and settling around him, blocking off his sight until even the ship's deck had vanished, and it was just him in the crow's nest's two square feet at the edge of the world and there was nothing else for all eternity. Chaos, he realised. He was back at the edge of Chaos again, his identity dribbling away slowly into the earliest void, voiceless and helpless.

 _The thing is,_ said the voice, _no one ever really leaves the pit._

"No!" Nico said aloud, but his voice was so thin and fragile under the roaring in his ears. "No, I'm still here!"

The fog cleared a little. Nearby, Nico could see the peak of a mountain, sharp black stone that reminded him of Mount Othrys. Standing on the summit was the twenty-foot-tall figure of a man wearing a Greek _chiton,_ with a flowing white beard and a wild, half-civilised look in his deep black eyes. He bellowed, raising his muscular arms high above his head. What was that in his hands – a boulder?

Nico should have realised what was coming, but his mind was sluggish and it took him a moment to register what the huge thump resounding around him was. The impact of the boulder had nearly thrown him off the rigging.

Leo sounded the ship's alarm bells, a high-pitched ringing sound that forced Nico to come back to himself. He began to clamber back down to the deck as the rest of the crew came running up from below, gathering to stare over the railings into the endless fog. From time to time they had brief, ghostly glimpses of more rock men.

" _Ourae,_ " Nico realised. "Mountain gods." Another rock missed the ship by barely a foot.

" _Numina montanum_?" Jason sounded uneasy. "They're sons of Gaia, aren't they?"

Coach Hedge bleated. "Who cares what they are? Tell me how to fight them!"

The next boulder came smashing into the ship's foremast, sending it flying away into the mist. Piper cried out as the ship tilted dangerously to port. "Leo, get us out of here!"

Leo obliged. They spurred backwards, retreating from the mountains into the sunny countryside again. The change was so pronounced that Nico wondered if the fog was magical.

Hazel hugged her sides. "What was that?"

Nico shivered. "The spirits of the mountains... if they're really Gaia's sons, they'll try anything to stop us crossing the Apennines."

"But what else can we do?" asked Jason. "We need to get to Epirus."

"Maybe we can find a pass in the mountains," Hazel said hopefully. "We just need to keep going north."

Leo looked tense, his expression humourless for once. He was staring at his bronze monitor, tapping his fingers. "Maybe," he said. "But I'm not seeing anything on the map. And we don't have that much time to waste."

"What if we go higher?" Frank suggested. "There must be a way over the mountains – not just through them."

Leo grimaced. "We can't gain that kind of altitude. But it might be worth trying the mountains again a bit later..." A sudden wicked gleam came into his dark eyes. "Once I've fitted out the ship with some new toys."

Nico didn't understand what he was talking about, but Hazel and Frank exchanged nervous looks. "The Archimedes sphere," Hazel said. "Are you sure you know what you're doing with that thing, Leo?"

Leo looked offended. "That _thing_ saved your guts in Rome. Show some respect."

Hazel rolled her eyes, but she was smiling a little. Inexplicably, Frank scowled.

Nico looked between the three of them. There was a tension there that he hadn't noticed before, in the guilty looks Hazel occasionally cast at Leo and the wistful ones he seemed to give back, and Frank glowering in the background, arms crossed.

Great. Just a boyfriend was more than enough to worry about. Nico _really_ didn't any further complications in his little sister's love life.

"Sammy Valdez," Hazel explained to him later. "Did I ever tell you about him?"

Nico thought for a moment. Hazel had told him a lot about her first life in the two weeks between when he'd brought her out of the Underworld and eventually led her to Camp Jupiter. And during his visits to New Rome, he'd always tried to make time to talk to her – but he didn't remember the name ever coming up before. Or maybe it was that Tartarus had dulled his memory, more subtly than the waters of the Lethe but cruel all the same. His life before the pit already felt so far away, as if it had happened to someone else.

"No," he said. The simple version.

Hazel's eyes were dark and sad. "Sammy was my friend in New Orleans," she said, but there was an extra edge to her voice, and Nico didn't need to be a child of Aphrodite like Piper to know what she meant. "I... I didn't see him again, after we moved to Alaska. But he grew up. He moved to Texas. And Leo is his great-grandson. Sammy died soon after Leo was born."

There was a lot she wasn't telling him, but Nico could hardly complain about that without becoming the world's biggest hypocrite. "That's quite the coincidence," he ventured.

Hazel shrugged. "Yeah. Or maybe Juno messing with our lives again. Apparently, she visited Leo a lot when he was little."

Nico didn't know what to make of that. Of all the gods to sponsor the quest for the ancient lands, of course it had to be Hera, with her disdain for anything that wasn't _proper_ and anyone who didn't fit into her perfect family. Hera, who'd paid Geryon for the safe passage of Percy, Annabeth, Grover and Tyson... but hadn't cared about Nico.

Why did he feel so bitter about it? The gods never cared about mortals. They only used them as their tools.

Hazel sighed, still lost in her own thoughts, and Nico put an arm around her shoulders.

 **oooooooooo**

An argument broke out at dinnertime: Frank was insisting that Leo's Archimedes spheres were dangerous, Leo was promising that they could work against the mountain gods, Piper was arguing that it wasn't safe enough for the ship to try crossing the mountains again, and Jason was unsuccessfully trying to take charge. Coach Hedge didn't help by claiming that he could single-handedly take down the entire tribe of _ourae_.

"Stop it!" Hazel banged the table hard. "This... this isn't what Percy and Annabeth would want."

The mood in the hall darkened.

For a long time, everyone was silent. Nico picked half-heartedly at a slice of pizza, conscious of his sister's worried eyes on him. To please her, he took a small bite.

"Nico," Hazel said quietly, breaking the silence, "where are you going to sleep tonight?"

Nico blinked. After his nightmare the previous night, he wasn't anxious to go to sleep again, but he could hardly tell her that. "I guess... in the sickbay again?"

Piper frowned. "That can't be very comfortable, with the statue's toes poking in like that."

"Why don't you take Percy's cabin?" Jason suggested quietly. "I mean... he's not using it."

"No!" Nico said, more violently than he meant to. The others all jumped. "N-no, I'll be fine in the sickbay."

It would be a special kind of torture to stay in Percy's cabin with Percy's clothes hanging in the cupboard, to sleep in Percy's bed and lay his head on Percy's pillow with Percy's alluring scent (like the sea on a stormy day) in his nose, and all he would be able to think off would be Percy dangling fifteen feet below him, drawing a promise that Nico did not want to give and could not help but give, because it was Percy asking.

Stumbling through Tartarus, his sanity slowly splintering, Nico had thought nothing could possibly be more painful. But the Fates always had a new surprise around the corner. Watching Percy fall into the pit had been more agonising than doing it himself.

Hazel and Piper were both staring at him. Feeling self-conscious, Nico got to his feet and left the mess hall. He hated having all these eyes on him, watching him all the time as if worried he would break into a million tiny pieces. He hated even more that they might be right.

 **oooooooooo**

Nico was standing at the entrance to the Mansion of Night, in a darkness so thick and soupy that it seemed to weigh on his lungs. Oizys, the goddess of despair, was stroking his hair softly, tenderly. It was the only kindness he'd had so far in the pit.

 _Isn't life hopeless, Nico di Angelo?_ the goddess murmured. Every brush of her fingers sent more despair running through him, dull and aching, numbing his fear and dimming his reason. He knew that if he stayed here much longer he would die, but Oizys kept whispering to him and he could not pull away.

 _Stay here,_ she whispered. _Sleep forever in the House of Night. No one will miss you, Nico di Angelo. No one cares that you are lost. You will always be alone._

The voice of the pit laughed cruelly. _Yes, stay here, son of Hades. You cannot get away so easily._

Nico jolted awake – crying again, but thankfully silently. He could still feel Oizys' fingers, soft and cool against his cheek. After all, there was something welcoming about despair, something freeing about giving up hope. He should know. His captivity in the bronze jar had almost been easier once he'd accepted that no one was coming for him, that he would die there unmourned.

 _You will always be alone._

Nico took a breath. He couldn't allow the dreams to get to him so much; he still had a quest to complete. If the memories would persist on coming to him in his sleep... well, then, he wouldn't sleep at all. He had to stay focused.

Once again, he got out of the sickbay and took a walk belowdecks, trying to slow his hammering pulse. Piper and Frank were on watch right now, but the rest of the crew must be sleeping in their cabins. He hesitated outside one door, despising himself for his weakness, and then pushed it open.

Percy's cabin was mostly bare. His bed was unmade, and a few clothes were hanging on the back of the chair beside the desk, but otherwise the place could have been empty for years. Yet Percy had been sleeping here, two nights ago.

Nico had been right; the room smelled like the sea. His eyes pricked with tears again, as if Oizys was still beside him.

Maybe she was. After all, no one ever really leaves the pit.


	3. Chapter III

**Disclaimer: I don't own Percy Jackson. All recognisable dialogue is taken directly from** ** _The House of Hades._**

 **A/N: Well, look who it is! I'm so sorry for the long wait between chapters - on the upside, I've now got quite a lot of this story written up, so expect weekly updates every Monday from now until I run out of chapters!**

 **Chapter III**

They tried crossing the mountains again the next morning, but the _ourae_ were still on watch; the _Argo II_ barely escaped with a few broken oars and the loss of Leo's newly-repaired foremast.

"It looked like a decent pass," Piper said glumly. "But they're on watch everywhere."

Leo scowled as he surveyed the damage. "I don't get it. The ship's supposed to mask the presence of demigods."

The others had come above deck to see what had happened. Now they gathered at the helm as the mountains faded into the distance behind them again.

"We've got to keep pushing on north," said Piper. "The ship can't take much more."

"But we can't let ourselves go too far north," said Hazel. "We don't have that much time."

And the crew exploded into argument again.

They would have probably gone on all day, if Leo hadn't put an end to the commotion by slapping a button on his monitor. An ear-splitting shriek rang out, making everyone simultaneously clap their hands over their ears.

"That's better!" Leo grinned around at them, but it didn't meet his eyes. "So, if we keep going north, we'll be coming up to Siena in an hour or so. Imma get me some supplies to repair that foremast, so what do you guys say to some shopping?"

"I could do with another pair of jeans," Frank said darkly. For some reason, he glared at Leo. Piper giggled.

"That's decided, then," Jason said, looking relieved. "Siena it is."

Hazel was looking anxious. As the impromptu meeting broke up, Nico drew over to her. "What's the matter?"

Hazel shook her head. "These _numina..._ I'm sure I heard something about them at Camp Jupiter... I'll be right back."

She ran off belowdecks without another word.

 **oooooooooooooooo**

After their shopping trip in Siena, the ship carried on flying north, looking for a safe pass over the mountains. It was a warm, sunny day, and most of the crew (bar Coach Hedge, who seemed to spend a lot of time in his cabin) were relaxing on deck.

Leo had sawed out a new foremast, and he was trying to set it up in place with the aid of Jason, who was casually flying up among the rigging. Sitting near them, Hazel and Piper had their heads bent over a map. Frank was standing at the railing amidships with his bow at the ready, staring out into the clear sky as if hoping an attack would come just to relieve the monotony.

Nico was in the crow's nest again. He leaned drowsily back in his perch, letting the summer sun caress his hair and face. He felt – well, not _happy_ exactly, but content. This was a good place, and a good day.

He was kneeling by the River Phlegethon and his hands were shaking. Logically, he knew that the fire water would keep him alive: he had to drink if he were to survive this place. But the horror of the pit kept beating down on him: the ground was his skin and the poisonous air was his breath and the river was his blood, and Nico could not bring himself to drink it any more than he could drink his own blood.

A bird called overhead and suddenly the vision dissipated. Nico remembered where he was, still on the _Argo II_ in the summer breeze, safe now, safe now. His throat still burned with the taste of the fire he'd forced himself to gulp down eventually, though he'd felt little better than a cannibal in doing so. _No._ He would not think of that.

He took a shuddering breath. All his muscles had locked in fright; with an effort, he forced himself to loosen them. What had happened? He hadn't fallen asleep, he was sure of that. He'd promised himself he wouldn't fall asleep again.

 _Well,_ his mind seemed to be saying, _if you won't remember when you're sleeping, you can remember while you're awake instead. Take THAT, sucker!_

Oh, gods of Olympus, shouldn't the worst be over now?

Or maybe the worst was yet to come.

 **oooooooooooooooo**

That night, Nico set up in the deserted mess hall just as Jason and Coach Hedge were going up for the first watch. The rest of the crew were settling down to sleep, but Nico had something to do.

He stared for a moment at the magical images on the walls, bathing the room in late-afternoon sunlight. One of them was showing the dining pavilion, and the long, sealed crack in its floor, like a scar. The crack he had made the day he'd learned of Bianca's death.

He shook his head. _Focus._ Then he raised his arms above his head and began to chant, his tongue forming the familiar Greek words as he were reciting a long-forgotten poem. Around the pile of meat and puddles of root beer at his feet, ghostly lights flickered.

He had not used any of his powers since he'd been captured. He'd been worried that it would drain him, but summoning the dead had always been easy. They were drawn to him, after all. Now they came in their droves, spirits kneeling to drink from the offerings. Nico drew his sword and kept them at bay, making sure that they drank enough to remember who they were but not enough to become substantial. After Minos, he'd learned some lessons.

The dead stood before him, waiting.

"I wish to know of the House of Hades," Nico said in Greek. "I must learn how to bypass the horrors within. Speak!"

The problem with summoning the dead was that you rarely got what you asked for. The mention of the House of Hades caused the spirits to stir, chattering nervously with their dry, dead, voices, and then they spoke all at once. _Children of the Underworld,_ they said. _Children of Death. An impossible foe. Two shall enter the temple. Only one will reach the Doors of Death. An impossible foe..._

Nico had heard enough. He raised his sword and slashed through the spirits, dispatching them back to the Fields of Asphodel. The temperature in the mess hall returned to normal. The ghostly lights vanished.

Nico cleaned up the mess he'd made on the floor, because he was considerate like that, and went to find Hazel.

She came to the door of her cabin looking bleary-eyed, and Nico immediately felt bad for waking her, but he didn't think his news could wait. "Hey. Can I... come in?"

Hazel rubbed her eyes and nodded. "Sure."

Her cabin was less bare than Percy's had been. All her clothes were neatly folded away, but she'd piled some mythology books on her desk, and some sketching pencils were stacked on top of a piece of paper. Nico's lips quirked up when he saw them. He'd bought those for her as a present once, when he'd visited her at Camp Jupiter.

Hazel sat down on her bed and patted the space beside her. "What's the matter, Nico? You should be sleeping."

Nico sat down and ignored the last bit. "I spoke to the dead," he told her, and then paused to see how she'd react. If he'd ever mentioned his powers to the demigods at Camp Half-Blood, they'd shy away from him, as if they thought that he, too, was a ghost. Even Percy had given him that half-afraid, half-disgusted look before.

(Nico did not want to think of Percy.)

But Hazel, loyal, sweet Hazel, showed no change of expression. She tilted her head a little to one side and said, "What did they tell you?"

Nico stared at his fingers. "They said two children of the Underworld will enter the House of Hades," he said. "They'll meet an impossible foe. Only one will reach the Doors of Death." There was no point mincing words.

Hazel was silent for a long time.

"You think one of us will die?" she asked at last.

"I don't know," Nico said, though the words seemed pretty clear. It wasn't fair. Hazel had already died so young once; she deserved a second chance. And he couldn't lose his sister, not again.

With a cold, settling certainty, he remembered the third line of the Prophecy of Seven: _An oath to keep with a final breath._

And what was Nico doing but keeping a promise – a promise to lead the others to the House of Hades? It all fit perfectly together.

"We can't worry about that right now," Hazel said. "It'll only distract us. What about the other part – the impossible foe?"

"I don't know," Nico said again. "It doesn't sound very cheerful."

Hazel exhaled, blowing a few strands of curly hair out of her face. "Okay. We can deal with this. We can talk to the others—"

"No!" She was starting to rise; Nico grabbed at her arm hard. "You can't tell the others. Not yet. Their courage is already stretched to the limit."

Hazel stared at him for a long moment. "You're right," she murmured. "But what are we going to do? How can we fight an impossible foe?"

Nico didn't like seeing such a desolate expression on her face. "We'll find a way," he said gently. "You saved me in Rome, didn't you? Against all the odds."

Hazel sighed and flopped down heavily on her bed, but she squeezed his hand. "Yeah," she said. "We did."

Nico got up to go, but Hazel caught at his wrist. "Will you... stay here with me?" she asked, sounding very young.

Nico nodded and lay down beside her. "Of course."

"You should sleep, too," Hazel murmured drowsily, nestling her head against his shoulder. Nico put his arm around her and listened as her breaths became steadier and deeper, but his eyes stayed open for a long time after.

 **oooooooooooooooo**

He, Hazel and Leo took the morning watch. Leo had set up some new weapons on the ship, and he was eager to try crossing the mountains one more time, but the attempt went wrong almost immediately.

The _ourae_ were still waiting for them. From his perch (at the top of the new foremast this time), Nico could see the boulders coming at them earlier than the other two could, but the ship was still taking a battering. Leo tried to manoeuvre out of the way of each rock, but the _Argo II_ was too large to turn nimbly.

"Hard to port!" Nico shouted for the fifth time, but this time Leo wasn't quick enough. A boulder came hurtling out of the fog and smashed into the base of the foremast. Nico wrapped his arms around the wood and clung for dear life as the mast toppled over again.

"Nico!" Hazel cried as he landed on the deck, wrapped in folds of the sail.

"I'm fine," Nico said, accepting her hand up. He wasn't even bruised, though his arms were covered in splinters of wood. From the bow, they could see more _ourae_ , bellowing angrily and hefting more rocks.

"Stupid rock gods!" Leo shouted. "That's the _third_ time I've had to replace that mast! You think they grow on trees?"

Nico almost rolled his eyes. "Masts _are_ from trees," he pointed out.

"That's not the point!" Leo snapped, jabbing at his controls. A cannon rose from a trapdoor in the deck and fired a stream of metal spheres wreathed in Greek fire. The _ourae_ roared, and another boulder came whistling past the ship.

"Get us out of here!" Nico said.

He and Hazel stumbled over to the helm as Leo turned the wheel and they retreated back into the morning sun.

"Well, _that_ was sucktastic," Leo said grumpily. "Should I wake the others?"

Hazel shook her head. "They need rest. We'll have to figure out another way on our own."

"Huh." Leo frowned at the map of Italy glowing on his monitor. "Another way. Do you see one?"

Hazel stared at the map. "It's our fault," she said uneasily. "Nico's and mine. The _numina_ can sense us." So that was what she'd been worrying about.

"Earth spirits don't like the children of the Underworld," Nico agreed. "That's true. We get under their skin – _literally._ But I think the _numina_ could sense this ship anyway. We're carrying the Athena Parthenos. That thing is like a magical beacon."

Leo traced his finger down the mountain range. "So crossing the mountains is out," he said. Nico wondered what it had cost him to admit it. "Thing is they go a long way in either direction."

"We could go by sea," Hazel suggested. She sounded strangely reluctant. "Sail around the southern tip of Italy."

"That's a long way," Nico pointed out. "Plus, we don't have..." Embarrassingly, his voice cracked. "You know... our sea expert, Percy." He managed not to stumble too obviously over the name, but then it hit him again, the memory as sharp and painful every single time: Percy was gone.

Hazel took a deep breath, as if trying to expel a cloud of sorrow from her lungs. "What about continuing north? There _has_ to be a break in the mountains, or something."

Leo fiddled with his console until it projected a 3-D hologram of the Apennines. "I dunno. I don't see any good passes to the north. But I like that idea better than backtracking south. I'm done with Rome."

Nico shivered, drawn suddenly back to the dull emptiness of the bronze jar. With an effort, he forced himself to focus. "Whatever we do," he said, "we have to hurry. Every day that Annabeth and Percy are in Tartarus..." He stared down at the rolling green hills. The enormity of the choice before them almost overwhelmed him. The crew had agreed to skirt north, but now they were considering turning around or even sailing the entire Italian coastline. "Maybe we _should_ wake the others. This decision affects us all."

"No," Hazel said firmly. "We can find a solution. We need some creative thinking. Another way to cross those mountains, or a way to hide ourselves from those _numina_."

Nico sighed as the obvious solution occurred to him. "If I was on my own, I could shadow-travel. But that won't work for an entire ship." He hesitated for a moment before admitting, "And, honestly, I'm not sure I have the strength to even transport _myself_ any more."

"I could maybe rig some kind of camouflage," Leo suggested half-heartedly, "like a smoke screen to hide us in the clouds."

Hazel stared glumly over the railing. They all stood in silence for a moment, thinking. North, east or south... none of the choices sounded appealing. _Choices._ Without quite knowing why, Nico shivered.

There was movement in the corner of his eye: a beige blur against the fields, racing towards them. Nico frowned at it, about to speak, but Hazel had noticed it too. Her eyes lit up. "Arion."

Nico blinked. "What?"

Leo whooped. "It's her horse, man! You missed that whole part. We haven't seen him since Kansas."

Hazel laughed, bright and happy. The beige dot had stopped on a nearby hill. Nico thought he could hear it whinnying. He remembered, now, Hazel's story of freeing the super-fast immortal horse from the Amazon headquarters in Seattle.

"We have to meet him," Hazel said. "He's here to help."

"Yeah, okay," said Leo. "But, uh, we talked about not landing the ship on the ground any more, remember? You know, with Gaia wanting to destroy us and all."

"Just get me close, and I'll use the rope ladder," Hazel said blithely. "I think Arion wants to tell me something."

Leo nodded and steered the ship towards the hill. Nico's neck prickled. On the summit of the hill next to Arion's, an inky-dark storm had gathered over some old Roman ruins. A funnel cloud hung ominously down. Whoever was generating it might as well have stuck up a big signpost reading _SOMETHING EVIL LIVES HERE._

The storm didn't bother Hazel. As soon as they reached the hill, she scrambled down the rope ladder and threw her arms around the handsome tan stallion. She spoke to him, but from a hundred feet above Nico couldn't make out the words.

"Hazel!" he called. "What's going on?"

"It's fine!" Hazel replied. She knelt down and then straightened. Gold gleamed in her hand before she held the nugget to Arion's mouth.

Nico blinked as it disappeared. "He eats _gold_?"

"Yeah," Leo said. "He's a bit of a snob."

Hazel was beaming up at them. "Arion wants to take me somewhere."

Nico and Leo exchanged nervous looks.

"Uh... Please tell me he's not taking you into _that_?" Leo pointed at the storm.

Hazel paled. She stared at the storm as if noticing it for the first time. Then she tossed her head of curls and climbed onto Arion's back. "I'll be okay!" she called. "Stay put and wait for me."

"Wait for how long?" Nico asked. "What if you don't come back?" Then he cursed himself; Hazel didn't need to hear that. But every instinct he had was telling him that his sister was in danger.

"Don't worry, I will," Hazel said confidently. She spurred her horse and disappeared in another beige blur, leaving only a vapour trail behind her.

Left alone with Leo, Nico stared at the black storm. His sharp eyes could just make Arion out as he disappeared into the darkness at the summit. "I don't like this," he muttered.

For lack of anything better to do, he walked over to where Leo was standing at the helm, fiddling with his monitor. "Do you... need any help?" he forced himself to ask.

Leo hunched his shoulders, looking as uncomfortable with Nico's company as Nico was with his. "Nah, I'm good."

Nico retreated a little way and studied him. He knew Leo was a year older than him, but he was shorter and almost as scrawny. He didn't look much like a fighter – but he could summon fire. He could send the entire ship up in flames, if he wanted to. Or even, Nico thought, remembering the Prophecy of Seven, the entire world.

He wondered if Leo still blamed himself for Percy and Annabeth falling into Tartarus. Hazel had explained to him about the fortune cookie Leo had used to save her life and Frank's, and about the price he'd had to pay for them. But, after all, if Nico had been just a little faster, he could have saved them.

For the next twenty minutes or so, he passed the time in silent, disheartening reflection, and although Leo was keeping his hands busy Nico suspected he was doing the same.

Finally, the black storm vanished. A moment later, Arion appeared directly beneath the ship in a blur of hooves. Hazel slipped off his back. She looked exhausted, but she managed to pat her horse's flank and to clamber up the rope ladder. Arion whinnied and then took off again.

"What happened?" Leo asked her once she had climbed aboard.

Hazel's hands were shaking. She stared over the rail at the dust of Arion's wake.

"Hazel?" Nico said worriedly.

Hazel's knees buckled. Nico and Leo each caught one of her arms and managed to help her to the steps of the foredeck. Nico examined her face. She looked unnerved, but otherwise fine.

"I met Hecate," she said. "At the crossroads at the top of the hill. She – she showed me which way we could go. She said there was a secret pass through the Apennines to the north, where the _numina_ can't sense us. And then from there she told us to go north to seek out the dwarfs in – in Bologna, I think? And then on to Venice, and down the Adriatic to Greece."

Her voice grew stronger as she spoke, but her eyes were still full of some unknown dread. Nico took her hand. "Hazel, you met Hecate at a crossroads. That's... that's something many demigods don't survive. And the ones who _do_ survive are never the same." He remembered stories he'd heard of demigods driven insane by the visions the dark goddess had shown them, literally maddened by choice. "Are you sure you're—"

"I'm fine," Hazel interrupted. But she didn't look as sure as she sounded.

"What if Hecate is tricking us?" Leo asked nervously. "This route could be a trap."

Hazel shook her head. "If it was a trap, I think Hecate would've made the northern route sound tempting. Believe me, she didn't." She shivered again, and Nico wondered what Hecate had shown her.

Leo tapped on a calculator he'd pulled out of his magical tool belt. "That's... something like three hundred miles out of our way to get to Venice," he said. "Then we'd have to backtrack down the Adriatic. And you said something about baloney dwarfs?"

"Dwarfs in Bologna," Hazel repeated, with a lot more patience than Nico would have had. "I guess Bologna is a city. But why we have to find dwarfs there... I have no idea. Some sort of treasure to help us with the quest."

"Huh," Leo said. "I mean, I'm all about treasure, but—"

Nico held a hand out to his sister, helping her to her feet. "It's our best option," he decided. "We have to make up for lost time, travel as fast as we can. Percy's and Annabeth's lives might depend on it." Again, the enormity of their task pressed down on his lungs.

"Fast? I can do fast." Leo hurried over to his console.

Once he was out of the way, Nico turned to Hazel, took her arm and guided her out of earshot. "What else did Hecate say? Anything about—"

"I can't." Hazel cut him off before he could ask about the House of Hades. Her eyes darkened, confirming Nico's suspicion that Hecate had told her a lot more than just how to cross the mountains. Then she stared guiltily at the floor. "I'll tell you later. Right now, we should rest while we can. Tonight, we cross the Apennines."

"Hazel—" Nico started, but she was already gone, hurrying belowdecks without meeting his eyes.

 **oooooooooooooooo**

Nico was on watch in the crow's nest late that afternoon as the ship raced north to Hecate's secret pass. The rest of the crew hadn't been happy to hear about the change in plans, but they'd all trusted Hazel to get them safely over the mountains. Now she and Frank were standing at the helm, talking in low voices. Amidships, Piper paced the deck, staring into her bronze dagger.

He had let his guard down again, lulled by the peaceful scene below him, and the memory took him by surprise: he was trudging aimlessly through the pit, the air burning his lungs and his limbs weak with exhaustion, and the horror of what he was walking over pressing constantly down on him. The worst part wasn't that the air was Tartarus' breath, or that the rivers were his blood or that every monster Nico saw was a tiny blood cell in the dark god's body. The worst part was the knowledge that Tartarus saw everything, knew everything – no, more than that. Everything that happened here was just a dream in Tartarus' mind, a figment of his dark imagination. Even _Nico_ was only here because Tartarus dreamt it so; he wasn't real. Nothing was real, outside the pit.

He knew, now, what Tartarus had meant when he said no one ever left the pit. Everything Nico was experiencing now was just a hallucination, his tortured mind unable to cope with the horrors he was really seeing: there was no _Argo II_ , no Hazel, no quest. There was only the pit.

 **A/N: So now we're back into canon events again - I hope you enjoyed! Please let me know in a review!**

 **~Butterfly**


	4. Chapter IV

**Disclaimer: I don't own Percy Jackson. All recognisable dialogue is taken directly from** ** _The House of Hades._**

 **A/N: Apolgies for the late update - there was an unforeseen lack of WiFi yesterday, but I hope you enjoy this new chapter!**

 **Chapter IV**

A few hours after sunset, Nico found Hazel at the ship's helm; she'd insisted on taking the wheel to guide them through Hecate's pass. She seemed intently focused on her task, so Nico was surprised when she said as he came up beside her, "You should be sleeping, Nico. It's not your watch."

" _Hazel_ ," Nico said, trying to keep his voice light. "Come _on_."

She looked at him like she was fighting back a smile or tears or both. "Sorry. I guess I just worry."

You should, Nico wanted to say. For a moment he wanted to tell her about the nightmares that plagued his sleep and the flashbacks that haunted his waking moments, to try and let her see some of the sharp broken mess inside him, but he knew he couldn't do it. For one thing, it would upset her. She didn't need to know what he'd seen in Tartarus. And then... he wasn't sure he wanted her to help him. Nico was barely a year older than her, but he quite liked feeling like her big brother, someone who protected her the way Bianca had always protected him. During the two weeks it had taken them to journey north from the entrance to the Underworld in LA to Camp Jupiter, she'd been weaponless and confused and awed by the modern world she'd found herself in, and he had been the one to fight off the monsters on their trail and teach her about the present. She'd relied on him almost completely during those first weeks in her second life, and as proud as Nico was of how she'd adjusted and made new friends, he didn't think he wanted to lean on her now.

"Nico?" Hazel prompted. Nico realised she'd been speaking.

He blinked and focused on her face. "Sorry, what?"

Hazel pursed her lips anxiously. "I was saying, did you want something?"

Nico glanced over his shoulder, to where Piper, Jason and Frank were all on watch. "I was thinking of summoning the dead again," he told her quietly. "Maybe I can learn something more about this obstacle in the House of Hades. But I won't do it if you don't want me to."

"Me?" Hazel sounded taken aback. "Why does it matter if _I_ want you to?"

"I know Hecate told you something about what we'll face there, Hazel. I... I don't want you to get upset."

Hazel looked thoughtful. She kept her eyes on the narrow mountain pass ahead of them, but she reached out to squeeze his hand. "Talk to the dead," she said finally. "Let's see if they have any useful advice. Then I'll tell you what Hecate told me."

Nico nodded and made his way belowdecks. He set up again in the deserted mess hall, but this time his chant was more focused: he needed a spirit who'd been to the House of Hades before, who could tell him something useful about how to navigate the tunnels of the temple.

The form of a young man solidified before him. His complexion was pale and waxy, even for a ghost's, as though he'd spent most of his life underground. He wore black robes and simple Greek sandals.

"Who are you?" Nico asked. "Speak." He had to do this quickly; he was tired today, worn out with lack of sleep, and even this small summoning was draining him.

The ghost's voice was like paper. "I was Glaucon, priest of Hecate. I served at the upper levels of the Necromanteion."

Nico frowned. A priest of Hades would have been preferable, but maybe this ghost would have some information on Hazel's new patron. "Tell me about Hecate," he said. "How can she help us fight the giants?"

The ghost frowned as if trying to remember. "In the first giant war, aeons ago, Hecate slew the giant Clytius."

"Clytius," Nico repeated. The name sounded heavy and cold; it seeped into his limbs like a shadow.

Glaucon nodded. "Clytius was the anti-Hecate, designed to swallow all magic. He was a dark giant, wrapped in shadows. But during their fight, the goddess used her torches to set his hair aflame. He burned to death."

"Burned to death..." Nico repeated thoughtfully. Perhaps Leo Valdez, too, had a part to play in the upcoming battle. "Now tell me about the temple. How did it work?"

"The House of Hades was where pilgrims spoke with the ghosts of their ancestors," said Glaucon. Was Nico imagining it, or was his form growing brighter, his voice getting stronger? "They would make offerings at different levels, and drink potions to enable them to see the dead." He paused, and his eyes glinted. "But you of all people, son of Hades, should know that summoning the dead is a dangerous business. Sometimes, the ghosts would be pleased with the offerings. But more often, the pilgrims suffered. Some disappeared in the lower levels of the Necromanteion. Others left the temple insane, or died soon after."

Nico shivered. "And how—?" he began, but his voice was failing him. Suddenly dizzy, he slumped against the long table behind him. Glaucon reached out an arm towards him, his eyes gleaming hungrily.

 _Summoning the dead is a dangerous business._

Minos had done this to Nico, years ago: fed off his own strength, reduced him to little more than a ghost himself as Minos' spirit grew stronger. Glaucon definitely looked more solid than he had earlier. But Nico was no longer a frightened grieving twelve-year-old; he took a deep breath, summoned all the power within him and slashed his hand through the ghost. He met with more resistance than he'd expected, like dragging his fingers through treacle. "Begone," he said firmly, and Glaucon vanished.

Nico fell to his knees, trembling. That had been a close call, and he hadn't got all the information he wanted. He didn't know how they could get safely through the House of Hades, nor exactly what was waiting for them at the Doors of Death.

He cleared up his pool of offerings and went to find Hazel.

 **oooooooooo**

She was quiet as he told her what he'd learned, nodding occasionally. "Hecate mentioned Clytius," she said. "But there's someone else waiting for us in the House of Hades: a witch. I... I think she's the impossible foe the dead told you about."

"A witch?" Nico said uneasily. "Like Circe? Or Medea?"

"Hecate didn't want to say her name," Hazel said. "But she said defeating her is my job. I need to learn magic."

They were both silent for a long time. Nico stared at his sister. "Magic," he said at last. "How?"

Hazel kept her eyes on the mountains they were flying through. "I don't know," she said. "Hecate said I must learn to use the Mist, like her children do. She said because I've returned from the dead, I – how did she put it? – I understand the veil between the worlds. But I don't know..."

Nico squeezed her arm. "You can do it," he promised, though even to his own ears the words sounded empty. Hazel wasn't a sorceress; she was just... Hazel. "I'm worried about how we'll even pass through the House of Hades. I – I didn't manage to get enough out of the ghost before—" He broke off. He didn't want to tell Hazel how close he'd come to disaster. Knowing her, she'd force him into the sickbay to rest again.

Hazel was too preoccupied to notice his hesitation. "Gaia plans to rise on August first," she murmured. "The Feast of Spes."

"The Feast of who?"

"Spes," Hazel repeated. "The Roman goddess of hope. It's, what, July fourth? That doesn't give us a lot of time to close the Doors of Death _and_ somehow defeat all the giants."

"One problem at a time," Nico reminded her. "Let's get to the House of Hades first and try to defeat our impossible foe. Preferably without either of us dying, which will only happen if we find out how to get through the temple."

"You've been there," Hazel said cautiously. "I know you don't want to talk about it, but do you remember how they brought you through?"

Ridiculously, Nico felt a little betrayed. Hazel had been so careful about asking him to remember up until now, but here she was telling him to draw up the memories he was trying so hard to keep buried. "No," he said shortly. "I don't." He turned to stare over the rail. Dark shapes were rushing below the ship, perhaps clouds or something more sinister.

"Nico..."

It was hard to stay angry with her. "I don't think I was conscious," he told her, taking her hand to show he'd forgiven her for asking. "Or maybe I was, in which case... I'm blocking it for a reason and I don't want to find out what." He was trying to sound brave, but his voice broke on the last word.

Hazel wrapped her arms around him. "I'm sorry," she breathed. "I know how hard it is for you." She didn't, though, she couldn't. "I wish I could help."

"It's getting better," Nico lied. "I just don't want to think about any of it."

Hazel's eyes were sad. She didn't say anything else, and Nico wasn't sure whether or not she believed him. He didn't know which would be worse.

 **oooooooooo**

Once they'd passed through the Apennines, Hazel insisted that Nico tell the others what he'd learned from the ghost, and so the next morning, after she'd handed the wheel to Piper and Coach Hedge, he reluctantly followed her down to the mess hall. Frank was already there, digging into some pancakes, and as they took their seats Jason came in with Leo on his heels.

Jason sat down uneasily at the head of the table, like he wasn't sure it was his place – strange, for a Roman praetor. "So," he said, "now that we're here... I guess we need to think about our next steps. We've crossed the Apennines, thanks to Hazel—" he flashed her a smile which she answered with a terse nod, "—but we should think about what happens when we reach the House of Hades. Nico?"

Nico leaned forward, feeling self-conscious with four expectant gazes on him. "I communed with the dead last night," he said. "I was able to learn more about what we'll face." He gave them the essentials of what Glaucon had told him about the House of Hades, managing to keep his cool despite several interruptions from Leo. Then he told them what he'd learned about Hecate. "She slew one of the giants – one who'd been designed as the _anti_ -Hecate. A guy named Clytius."

"Dark dude," said Leo. "Wrapped in shadows."

Hazel narrowed her eyes. "Leo, how did you know that?"

Leo shifted in his seat. "Kind of had a dream. He – the giant – he was chasing me through Camp Half-Blood, except the place was in ruins... there were the bodies of demigods everywhere." He shuddered. "I saw Octavian speaking in Gaia's voice, saying the Romans are advancing on camp. Then I got to Half-Blood Hill, but it wasn't like it was supposed to be. It had a cliff dropping off on one side and you couldn't see the bottom, just clouds. There was a woman there. Not Gaia. She said I had two choices: I could jump off the cliff or go into this cave that had opened up there. She said, _The House of Hades awaits. You will be the first puny rodent to die in my maze_."

Nico shivered. Surely, this could only be Hazel's sorceress.

"So the giant is Clytius," said Jason. "I suppose he'll be waiting for us at the Doors of Death."

"And the woman in Leo's dream?" Frank asked between bites of pancake.

Hazel had summoned a diamond from somewhere and was twirling it between her fingers. Nico wondered how she did that when they weren't technically on solid ground. "She's my problem," she said. "Hecate mentioned a formidable enemy in the House of Hades – a witch who couldn't be defeated except by me, using magic."

"Do you know magic?" Leo asked.

Hazel's lips thinned into a line. "Not yet."

"Ah. Any idea who she is?"

Hazel shook her head. "Only that..." Her eyes met Nico's. She looked as if she wanted to tell the others what he'd found out in his first conversation with the dead. Nico gave her an alarmed look. She couldn't tell them. It wasn't their burden to bear, and they'd only grow more afraid. "Only that she won't be easy to defeat," she said at last, and Nico relaxed.

"But there _is_ some good news," he said. He explained what Glaucon had told him about Clytius' defeat. "In other words, fire is his weakness."

They all looked at Leo, who didn't look happy – as if there were more to his dream than he'd said. "Oh," he said at last. "Okay."

Jason nodded. "It's a good lead. At least we know how to kill the giant. And this sorceress... well, if Hecate believes Hazel can defeat her, so do I."

Hazel didn't look pleased with the compliment. "Now we just have to reach the House of Hades, battle our way through Gaia's forces—"

"Plus a bunch of ghosts," Nico pointed out. "The spirits in that temple may not be friendly." If they were anything like Glaucon, they might be the most dangerous enemy in the tunnels.

 _A dangerous enemy._ Why did the words stir some recognition within him?

He knew, then, that he _had_ been conscious when the giants had brought him through the temple. Perhaps only barely – though he didn't remember exactly, he was sure coming through the Doors of Death hadn't been exactly healthy – but there were memories there, pressing at him again, longing for recognition. But _he could not let them in._

He'd completely zoned out. "Let's focus on the things we can deal with," Jason was saying. "We're getting close to Bologna. Maybe we'll get more answers once we find these dwarfs that Hecate—"

He broke off as the ship lurched violently. The force threw Nico out of his chair; the last thing he knew was a sharp pain in his head before he blacked out.

When he opened his eyes again he was back in the sickbay, Hazel leaning worriedly over him. Nico's head was throbbing, but he tried to sit up.

"Thank the gods," said Hazel. "Here." She held a glass of nectar to his lips and he took a few cautious sips, until his headache vanished. He wished all his problems could be solved that easily.

"What happened?" he asked.

Hazel frowned. "I think those dwarfs turned up. I'm not sure. You were out for a while."

Nico looked around. "How'd you even bring me here?"

Hazel arched her eyebrows. "I carried you."

"Oh." Nico looked away from her. He'd known he was underweight, but he hadn't realised how much the long starvation had affected him. Great. Now Hazel would press him even more. "We should get back to the others," he said, to change the subject. "They might need help."

Getting back was harder than anticipated. Nico was feeling better, but it turned out he was still quite dizzy, and he nearly fell more than once. "I hope you don't have a concussion," Hazel said anxiously. "You can't take much more nectar."

Still, Nico made it above deck eventually, where they found Frank sitting beside the rail, looking dazed, and Coach Hedge ranting at Piper, who was ignoring him and peering into the blade of her dagger. "Stupid knife," she said irritably as they approached. "It never shows me what I want to see."

Hazel left Nico's side and ran over to her boyfriend. "Oh my gods, Frank, are you okay?"

Frank rubbed his head. "Yeah, I think so. The dwarfs set off one of Leo's grenades."

"Where are they?" Hazel asked. "Leo and Jason?"

"They went after them," Piper said. "The dwarfs took Leo's tool belt. He was _not_ happy."

"There they are," Hazel said. Shielding his eyes from the sun, Nico followed her gaze. Jason was flying back to the ship, holding Leo's arm firmly. He landed effortlessly on the deck, not even looking drained by the effort.

Leo was wearing his tool belt, and holding a large leather-bound book in one hand. His face was a little sooty, but he looked otherwise none the worse for his adventure as he grinned around at them. "So here's our treasure!"

Piper leaned her head against Jason's shoulder and eyed it doubtfully. "A book?"

Leo nodded. "The dwarfs stole it from a minor god in Venice, apparently. It's got to be it. And they gave us an address – I got them to write it down as well. Ten out of ten, or what?"

Frank scowled. "A minor god? Which minor god?"

Leo shrugged. "Dunno. They, uh, couldn't pronounce his name. Something with T?" He turned to Jason, who'd been silent up until now.

Jason nodded. "Truh-something. But hey, we've faced worse than some minor god. We'll manage it." He glanced tentatively at Hazel. "Hecate told you we've got to get to Venice, right?"

Nico didn't know why his sister disliked Jason, but he was convinced she had something against the Roman praetor. Sure enough, Hazel's voice held none of her usual warmth as she said, "Yeah. I guess we'll find something to help us get through the House of Hades..." She trailed off, flashing Nico an uncertain look, but said nothing more.

Leo was at the helm now, listening to the whistling, creaking sounds his metal dragon was making. "Festus says we're about a day away from Venice," he reported. "We should get there tomorrow morning. Until then..." He looked expectantly at Jason.

Jason raised his eyebrows. "Until then, let's do what we usually do and try not to die," he said.

The meeting disbanded.

 **oooooooooo**

Up in the crow's nest, Nico tried to sort through the muddle of longing and apprehensiveness he found himself in. Venice... his mother was from Venice. His father had told him that much when he'd pressed. But he was sure there was more to it than that, a connection he didn't know about, struggling to break through the mists of Lethe water and seventy years of separation.

It had been like this ever since he'd seen that scene in Persephone's garden and learned the truth about his mother's death: maddeningly faint memories taunting him at the shadows of his mind, always flitting away too fast for him to catch. Nico didn't know why he remembered anything of his past: he'd been dipped in the Lethe, and that should have erased his memory permanently. Maybe, as a son of Hades, the rivers of the Underworld didn't affect him the way they did other demigods. That would explain why he'd felt so weak in Tartarus, even when he'd forced himself to drink from the Phlegethon... He pushed that train of thought away. Or maybe it was because learning about his bath in the River of Forgetfulness had undone some of its effects.

He'd been born in Venice, hadn't he?

An image flickered, almost too fast to absorb: Bianca holding his hand and walking him along the Grand Canal, pointing out the buildings that they passed. His mother was there, too, on his other side, wearing an elaborate 1930s hat and elegant gloves, but it was his sister's face he remembered most clearly, her gentle voice and the way her eyes sparkled when she smiled. The sound of her laugh when he asked a silly question and the animation with which she used to tell him bedtime stories. The warmth of her arms after they'd had a narrow escape from one of the horrors they'd never really understood and which no one else could see.

Nico had worshipped her.

He wasn't even remembering his childhood now, he realised: just Bianca, who'd been mother and father to him both, far more than Maria di Angelo could have been; Bianca, who'd protected him for eleven years (or eighty) and then abandoned him. He still didn't understand her choice. He still couldn't forgive her.

 **oooooooooo**

There was a storm that night. Nico climbed above deck to watch as Jason tried to fight off the wind spirits attacking and Leo struggled frantically to keep the ship straight. Hazel had been on watch, too, but just as Nico came up she staggered back to the trapdoor, stumbling into him as she went. Her curly hair was dark with rain, clinging to her wet face and neck.

"What are you doing?" she cried over the roar of the wind. "Get below deck!"

Nico didn't answer. He let her go back down and then struggled over to the nearest mast, clutching it for support. The other boys hadn't noticed them, preoccupied as they were, and though Nico wanted to help he doubted he could make much of a contribution.

Tilting back his head, he let the rain beat down on his face. The relentless battering of drops against his cheeks and eyelids felt like a cleansing, taking away his dizziness and his headache and the ever-present weakness in his limbs. The memories remained, though.


	5. Chapter V

**Disclaimer: I don't own Percy Jackson.**

 **Chapter V**

When the _Argo II_ set down in one of Venice's wharfs the following morning, Nico ran over to the starboard railing to take a good look. The city was filled with red-roofed buildings and crisscrossed with gleaming green canals through which gondolas drifted lazily. Looking at it, Nico felt a rush of something a little bit like homesickness, and a little bit like yearning. His buried memories seemed to be bubbling to the surface of his brain. This was _his_ city. Those canals ran in his blood.

The crew all gathered at the railing. Soon the topic of conversation focused on the weird cow-monsters prowling the streets. Looking at them, Nico was sure he'd seen them before somewhere. But he knew he'd never fought anything like that before, so how could he have?

"We'll have to walk through them and hope they're peaceful," Frank said nervously. "It's the only way we're going to track down the owner of that book."

" _La Casa Nera,_ " Leo read from the sticky note he'd put on the front of the leather book. " _Calle Frezzeria_."

"The Black House," said Nico. "Calle Frezzeria is the street." Then he blinked. Yes... he spoke Italian. Of course he did. And suddenly his mother's voice filled his ears, the gentle lilting Italian lullabies she'd sung him as a baby. Styx and Cocytus... he'd forgotten so much.

Frank looked at him curiously. "You speak Italian?"

The subject was too new and tender for Nico to want to talk about it. He gave Frank a hostile look but said, "Frank is right. We have to find that address. The only way to do that is to walk the city." He stared at the sprawl in front of them, remembering suddenly how easy it had been to get lost in those narrow, winding streets. "Venice is a maze," he continued. "We'll have to risk the crowds and those..." For a moment, the name of the shaggy cow monsters seemed to be on the tip of his tongue, but then it slipped away again. "...whatever they are."

Thunder rumbled overhead, and Jason frowned. "Maybe I should stay on board. Lots of _venti_ in that storm last night. If they decide to attack the ship again..."

"Well, I'm out, too," Coach Hedge grunted. "If you softhearted cupcakes are going to stroll through Venice without even whacking those furry animals on the head, forget it. I don't like _boring_ expeditions."

Leo replied, but Nico wasn't listening. He gazed at the city again, extending his senses. Despite the midmorning heat, the streets seemed to be exuding cold. There were ghosts in Venice, and he wasn't sure they were friendly.

"I'll go," Frank said.

"Awesome," said Leo, handing him the book. "If you pass a hardware store, could you get me some two-by-fours and a gallon of tar?"

"Leo, it's not a shopping trip," Hazel reproached.

"I'll go with Frank," Nico broke in.

Frank's eye twitched. He looked uneasily at Nico, who bit back a smile. Frank was probably at least twice his size, and yet he looked _terrified_ of Nico. Well, good. A big brother couldn't be too careful with his sister's boyfriend. But a small, sad part of him wondered how anyone could be afraid of someone as broken as he was.

"Uh... you're good with animals?" Frank asked.

Nico smiled thinly. "Actually, most animals hate me. They can sense death. But there's something about this city..." He couldn't tell them how desperate he was to see the city where he'd been born, to walk the streets he'd grown up in seventy years ago. "Lots of death," he said. "Restless spirits. If I go, I may be able to keep them at bay." He raised his eyebrows at Frank. "Besides, as you noticed, I speak Italian."

"Lots of death, huh?" said Leo. "Personally, I'm trying to avoid lots of death, but you guys have fun!"

Hazel shot him an annoyed look, slipping her arm through Frank's. "I'll go, too. Three is the best number for a demigod quest, right?"

Nico didn't reply immediately, staring at the city again – _his_ city. "All right, then," he said at last. "Let's go find the owner of that book."

He led the way down the rope ladder and into the city.

 **oooooooooooooooo**

They didn't talk much as they walked through the city. Hazel and Frank seemed to be content walking a little behind Nico, holding hands. They skirted past tourists and cow monsters alike, tracing the path of one of the canals. Nico kept his eyes open for both the Black House and any links to his old life, but none came – at least until they turned onto a smaller street.

Ahead of them was a small plaza which radiated cold, and Nico's neck prickled with the uneasy feeling that dozens of _lemures_ were watching them, waiting to attack. A crowd of cow monsters were milling around in the plaza. But beyond that... a little side street led off the courtyard, and one of the houses on it was jet black.

"There," he said, stopping.

Frank squinted ahead. "A lot of cows in one place."

"Yeah, but look," Nico said. "Past that archway."

Frank was really squinting now. At last, he seemed to see the house. "La Casa Nera."

"I don't like that plaza," said Hazel nervously. "It feels... cold."

Nico nodded, impressed. Hazel's ability to sense ghosts had improved a lot. "You're right, Hazel. This neighbourhood is filled with _lemures._ " He concentrated, trying to send off a stay-away message to the ghosts.

"Lemurs?" said Frank. "I'm guessing you don't mean the furry little guys from Madagascar?"

"Angry ghosts," Nico explained. " _Lemures_ go back to Roman times. They hang around a lot of Italian cities, but I've never felt so many in one place. My mom used to tell me..." He trailed off, suddenly caught up in the intensity of the memory: his mother's warm voice as she murmured stories to him before he went to sleep, the way a smile seemed to have tinted every word she spoke. _Never be afraid of ghosts, darling,_ she'd told him. _They are your birthright._ "She used to tell me stories about the ghosts of Venice."

Frank looked at him curiously. "Nico, your mom was Italian? She was from Venice?"

Nico didn't want to talk about her, but he also wanted to talk about her more than he'd ever wanted anything in his life. Reluctantly, he nodded, recalling what his father had told him about her last summer. "She met Hades here, back in the 1930s. As World War Two got closer, she fled to the U.S. with my sister and me. I mean..." He glanced apologetically at Hazel; he knew she'd never liked it when he brought her up. "Bianca, my other sister. I don't remember much about Italy, but I still speak the language."

Frank's eyes were unreadable. "Must have been hard on your mom," he said at last. "I guess we'll do anything for someone we love."

 _Lead them there! Promise me!_

Nico inhaled sharply and stared at the floor so he didn't have to meet their eyes. "Yeah," he said, trying and failing to keep the bitterness from his words. "I guess we will."

Luckily, Frank changed the subject. "So, the _lemures_... how do we avoid them?"

"I'm already on it," said Nico. "I'm sending out the message that they should stay away and ignore us. Hopefully that's enough. Otherwise... things could get messy." Between the cow monsters and a host of unfriendly ghosts, he _really_ didn't like their chances.

"Let's get going," said Hazel, sounding as apprehensive as he felt.

They picked their way carefully across the square: Frank in the lead, Hazel following and Nico bringing up the rear. For some reason, as she walked Hazel kept her hand on her jacket pocket. Nico didn't even understand why she was wearing a jacket in the sticky heat, but now he realised that he'd seen her put her hand protectively over her pocket a lot.

At any rate, with one hand on her chest, Hazel's balance was a little precarious, and as they skirted around the well in the middle of the plaza she tripped on a loose piece of cobblestone. She would have fallen in Frank hadn't caught her, but the damage was already done. At the demigods' feet, the green roots that the monsters liked to eat began to crawl towards them. The beasts made angry sounds deep in their throats.

"Nice cows," Frank said, edging around Hazel and Nico to put himself between them and the monsters. "Guys, I'm thinking we should back out of here slowly."

"I'm such a klutz," Hazel whispered. "Sorry."

"It's not your fault," Nico said. "Look at your feet." As he spoke he took a step backwards, but the roots followed him. Poisonous vapour curled off them. For a moment, Nico's vision flickered, like a memory was trying to force its way to the surface, but he pushed it back down.

"These roots seem to like demigods," Frank was saying.

"And the cow creatures like the roots," said Hazel.

Frank looked uneasily at the angry herd. "Don't meet their eyes. I'll distract them. You two back up slowly towards that black house."

Hazel didn't look happy about that, but she nodded. Nico was about to take a careful step backwards when the creatures tensed as if about to charge.

"Never mind," Frank said. "Run!"

Hazel snatched at Nico's hand and they made a dash for the side street. He wanted to protest that he didn't need her help, but he had no breath to do so, so perhaps the argument was invalid. He still wasn't back to full strength.

They would have made it to the black house if two of the cow monsters hadn't started to chase after them, charging a lot faster than demigods could run. Realising that fleeing wasn't an option, Nico let go of Hazel's hand and as one they turned and drew their swords. Two against two – it should have been easy. The monsters didn't even look that dangerous. As Nico raised his blade, poisonous green vapour from the creatures' breath curled towards him. His muscles locked.

 _Poison._ He wasn't there any more, in a sunny plaza in Venice: he was standing in Tartarus, near the edge of Chaos, and the goddess Akhlys was cackling at him as she showed him all the deadly plants in her domain, larkspur and aconite and foxglove. _Choose, child of Hades!_ she'd said. _Which will stop your heart?_

The worst part was that, for a moment, he'd felt tempted.

Something brushed against his side and then he was back in the present and Hazel had fallen against him, eyes already half-closed, a cloud of green gas hanging over her face. Nico cried out, grabbing her shoulders and dragging her out of harm's way before turning back to the monsters. Terror made him quick and ruthless and before he could even think the cows were two puddles of shadow at his feet.

Then he knelt beside his sister, propping her against a wall. Her eyes were closed and her skin was taking on a greenish tinge. Oh, gods... this was all his fault. He forced himself not to panic, but it was difficult when he glanced back at Frank in the form of a lion, also retching through a cloud of gas.

Nico called out to him, shaking Hazel's shoulders all the while, but she didn't stir. Nico couldn't tell if she was breathing. She wasn't dead, she couldn't be dead. He couldn't lose another sister. But wouldn't his father think it hilarious to punish Nico for bringing Hazel back from the dead this way? He gestured at Frank to hurry.

Frank had changed back into human form. He took in the situation and dashed towards them; amazingly, the monsters stayed away as he ran over and grabbed Hazel's shoulders.

"She got a blast of green gas right in the face," Nico said, fighting back frightened tears. "I – I wasn't fast enough."

Frank stared at him. For once, he didn't look afraid of Nico, just furious. His eyes flickered with flames, and for the first time he looked to Nico like a child of the war god. "We need to get back to the ship."

The cow monsters bellowed, and the foghorn sound echoed with an answering call from nearby streets. "We'll never make it on foot," Nico said urgently. "Frank, turn into a giant eagle. Don't worry about me. Get her back to the _Argo II_!"

A cool voice behind them said, "Your friends can't help you. They don't know the cure."

Nico jerked around. On the threshold of the Black House, a young man was standing. He was dressed casually in denim, but there was no aura of mortality around him: he was a god, if a minor one. He had curly black hair and a smile that was friendly, but also distant.

"Can you cure her?" Frank asked.

"Of course," said the god. "But you'd better hurry inside. I think you've angered every _katobleps_ in Venice." He stepped aside and gestured for them to follow him into the house.

Nico picked up his sword to guard Frank's back as he bent to gather Hazel up into his arms like a rag doll. Then both boys bolted for the front door, just barely making it inside before the cow monsters attacked.

"Oh, they can't get in," the man said as he threw the bolts. "You're safe now!"

"Safe?" Frank said angrily. "Hazel is dying!"

"Yes, yes, bring her this way," said the man, leading them further into the house.

Frank hoisted Hazel into a better position and made to follow. "Do – do you need help?" Nico asked.

"No, I'm fine," Frank said, walking without any signs of difficulty. His voice was curt, and Nico thought he could hear the undertones: _You've done enough._

Their host led them through an indoor greenhouse into a garage lined with computers and with a huge red-and-gold chariot parked against one door.

"Set your friend here," said their host.

Frank lowered Hazel down onto the bed against the right wall. "What were those cow things?" he demanded. "What did they do to her?"

" _Katoblepones,_ " said the god. "Singular: _katobleps._ In English, it means _down-looker._ Called that because—"

"They're always looking down," Nico said. He smacked his forehead, feeling furious with himself. "Right. I remember reading about them now."

Frank glared at him again. " _Now_ you remember?"

Nico stared at his feet. "I, uh... used to play this stupid card game when I was younger," he said. "Mythomagic. The _katobleps_ was one of the monster cards."

He waited for Frank to laugh at him, but when the other boy spoke he just sounded confused. "I played Mythomagic. I never saw that card."

"It was in the _Africanus Extreme_ expansion deck," Nico explained.

"Oh."

The man cleared his threat very audibly. "Are you two done, ah, _geeking out,_ as they say?"

Nico flushed. For a moment, the man's voice sounded exactly like those of the jeering kids at Westover Hall. "Right, sorry. Anyway, _katoblepones_ have poison breath and a poison gaze. I thought they only lived in Africa." He strained his memory, trying to recall the other facts that had been on that little purple card, but they were gone as surely as the card itself, fed into the flames.

"That's their native land," said their host. "They were accidentally imported to Venice hundreds of years ago. You've heard of Saint Mark?"

Nico didn't want to listen to the history of how the monsters had arrived in Venice – only what they had done to his sister, and how he could save her. He drew near enough to the bed to examine her. She was shivering, her skin growing greener. As he'd held her hand and led her across the Styx, months ago, her life aura had burst into dazzling brilliance, the colour of purest gold. Now it was waning again, becoming fainter. Nico couldn't tell how long she had left.

"Got it," Frank said sharply. "Can you cure her?"

"Possibly," the god said, with a nonchalant shrug.

Nico thought Frank might burst a vein as he said, " _Possibly?_ " He put his hand worriedly against Hazel's face as if checking for her breath. "Nico, please tell me she's doing that death-trance thing, like you did in the bronze jar."

Nico grimaced, trying not to succumb to the hollow despair he'd felt during his captivity, knowing that no one was coming for him. "I don't know if Hazel can do that," he said. "Her dad is technically Pluto, not Hades, so—"

"Hades!" cried the man. His expression was _so_ familiar, that mingled fear and disgust that Nico always saw when he announced his parentage, as if Nico himself was a walking corpse. "So _that's_ what I smell. Children of the Underworld? If I'd known _that,_ I would have never let you in!"

Frank jumped to his feet. "Hazel's a good person. You promised you would _help_ her!"

The god sniffed fastidiously. "I did _not_ promise."

Nico drew his sword, rage and panic mingling intoxicatingly in him. "She's my sister," he said, voice low and threatening, trying to channel as much of the scary child-of-Hades vibe he could. "I don't know who you are, but if you can cure her you have to, or so help me by the River Styx—"

The man didn't look even slightly afraid. "Oh, blah, blah, blah!" he said, waving his hand airily, and Nico's vision went dark.

 **oooooooooooooooo**

He dreamed that he was in one of the movie theatres in DC, which he and Bianca had occasionally gone to back when they'd lived in the city. Someone was trying to offer him popcorn, and Nico was refusing, saying he didn't want any – which was weird, because he really liked popcorn. He was trying to tell the person that he didn't want it buttered, but then the person got angry, and Nico realised it wasn't even a person: it was a small diapered baby with wings, fangs and skin tinted green with chlorophyll, like a dryad's. "Corn!" it shrieked. "You will have corn!"

Nico tried to protest that he didn't want any, but then the baby burst into an explosion of buttered popcorn, and more started filling the room, the walls crumbling to reveal endless avalanches of popcorn pouring in and choking him.

His eyes flew open and he gasped. He was back in La Casa Nera, still standing beside the bed. "I – I had the weirdest nightmare about popcorn." His eyes darted around the room, taking everything in quickly: Hazel sitting up and conscious, the green colour gone from her face and her life aura strong and healthy again; the god standing irritably at the foot of the bed; and Frank – _Frank._ Frank, who was some three inches taller than he'd been before, muscled and solidly built, with a broad chest and powerful shoulders. "Why are you _taller?_ " said Nico.

"Everything's fine," said Frank calmly. "Triptolemus was about to tell us how to survive the House of Hades. Weren't you, Trip?"

Triptolemus... the god of farming. That explained the uncomfortable feeling in Nico's limbs, like he'd briefly been turned into something growing. Unfortunately, his stepmother had made him very familiar with the sensation of being a plant.

"When you reach the House of Hades," the god was saying, "you will be offered a chalice to drink from."

Nico didn't like the way he phrased that. "Offered by whom?"

"Doesn't matter," Triptolemus said sharply. "Just know that it is filled with deadly poison."

"So you're saying we shouldn't drink it," said Hazel. She looked as though she'd had more than enough poison for one trip.

"No! You _must_ drink it, or you'll never be able to make it through the temple. The poison connects you to the world of the dead, lets you pass into the lower levels. The secret to surviving is – _barley._ "

"Barley," Frank repeated.

Triptolemus nodded like they were having a totally normal conversation. "In the front room, take some of my special barley. Make it into little cakes. Eat these before you step into the House of Hades. The barley will absorb the worst of the poison, so it will _affect_ you, but not kill you."

Nico couldn't believe what he was hearing. The days they'd wasted on the long detour seemed to flash tauntingly before his eyes. "That's it? Hecate sent us halfway across Italy so you could tell us to eat barley?"

"Good luck!" said Triptolemus, jumping into his chariot. He spoke a few incomprehensible words to Frank before crying, "I will teach them the glories of tilling, irrigation, fertilising! Away, my serpents! Away!" He flew off through the open garage door.

For a few moments none of them spoke. "That was very strange," said Hazel. It seemed like a fair summation of the situation.

"The glories of fertilising," Nico said drily, brushing corn silk off his shoulder. "Can we get out of here now?"

Hazel hesitated, standing up to put her hand on Frank's shoulder. "Are you okay, really? You bartered for our lives. What did Triptolemus make you do?"

Frank's eyes were watery and his hands had started to tremble just a little, as though he was going into shock. "Those cow monsters... the _katoblepones_ that poisoned you... I had to destroy them."

Nico raised his eyebrows, impressed. He'd clearly underestimated Frank before today. "That was brave. There must have been, what, six or seven left in that herd."

"No," Frank said, clearing his throat. "All of them. I killed _all_ of them in the city."

Nico stared at him. Hazel didn't move, either. How could that even be possible? He was tempted to think Frank was joking, except he looked very serious.

Hazel seemed to believe her boyfriend, too. Standing in her toes, she reached up to kiss Frank's cheek. Her eyes were soft and sad and her smile looked fragile.

Nico couldn't stand seeing his sister look so upset. "Well," he said lightly, trying to brighten the mood, "does anyone know what barley looks like?"

It worked. Hazel and Frank exchanged rueful smiles. "We do, unfortunately," said Hazel. "Ran into some _karpoi_ on our quest to Alaska."

" _Karpoi_?"

"Grain spirits," Frank explained. "You don't want to meet them."

Nico thought about the weird dream he'd had. "I believe you."

True to word, Hazel easily identified the store of barley in Triptolemus' front room. They stuffed the grain into some canvas bags and made their way out of the Black House and back through the city.

Frank hadn't been joking. There was not a single _katobleps_ left on the streets of Venice. Nico stared at him in awe. "How did you...?"

Frank shifted uncomfortably, but as they walked he told them how he'd promised to fix Triptolemus' chariot by finding him a python – and how his father had told him that he would only get one as a reward for cleansing Venice, slaying the cow monsters one by one on a bridge just like Horatius had defeated Rome's enemies. Hazel kept smiling throughout, like she'd always known what Frank was capable of, but Nico was too stunned to speak. Frank had acted like a true hero. He'd got the information they needed from the god _and_ made sure that Hazel had been cured. Meanwhile, Nico had let his sister get poisoned in the first place, and instead of doing anything helpful he'd irritated the god and been turned into a corn plant.

He no longer wanted to spend time looking around Venice. Better to get out of the place as quickly as possible. Better to keep running, always.

Back on the _Argo II_ , Nico settled himself atop the newly-repaired foremast without speaking to anyone. Hazel shot him a concerned look as they climbed up, but then the ship started sailing down the Adriatic and she had more pressing concerns. She staggered and then stumbled below deck, looking as though she wanted to throw up.

Nico watched Piper exclaiming over Frank's new muscles while Leo ribbed him good-naturedly and Jason watched the clear blue sea, his face unreadable. Nico leaned back until the hard wood of the mast pressed uncomfortably into his back and tried to ignore the cold pit of shame in his stomach.

The scent of the sea and the ocean spray on his face didn't help: it only reminded him of Percy, looking up at him from fifteen feet below with brilliant green eyes that were shining with terror and determination all at once – Percy, who'd chosen Annabeth's hand and mortal danger over Nico's and safety – Percy, whom he hadn't saved.

Another failure.

 **A/N: This is one of my favourite chapters so far. Rereading HoH, Nico has a lot going on during the Venice episode, and even more when you think about the fact that he's visiting the city of his birth for the first time in seventy years... Anyway, I really hope I managed to do this justice, and reviews are always appreciated!**


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